Just one small comment on suitable production paper.
It would be nice if paper manufacturers could contribute and send a list of
suited paper for production printing to Fogra 51 and Fogra 52 by doing
their own measurement with M1, - which would make that paper suited for
printing according to ISO 12647-2-2013.
I have not done a lot of measurements, but the specs I have found about
commercially available papers either have nothing about white point to D50,
- or the measurement is M0 and the suggested profiles for the paper are the
old Fogra 39 / Fogra 47 - based on the M0 measurement (even if the paper is
almost perfectly correct for printing according to the current ISO standard
according to my own measurements). That again means that the paper is in
fact NOT suited for printing according to Fogra 39 / Fogra 47 because of
the OBA that is ignored when measured with the M0 filter.
There are however no doubt papertypes out there that, when measured with
the M1 - and M0 condition are appropriate for printing according to Fogra
39, Fogra 47.
In fact it would be useful if Fogra would start offering paper
manufacturers to certify their production paper as suited for commercial
printing according to Fogra 51 / Fogra 52.
It would surely make my life easier if I could look the suitable papers up
on the Fogra website, - and I'm sure for many others as well, - even just
color conscious print customers and designers that would prefer to keep
their colors in check cross media.
Best regards and wishing you a nice weekend
Ingi Karlsson
fös., 1. mar. 2019 kl. 02:36 skrifaði <
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Today's Topics:
1. Re: Issues related with the switch from FOGRA39/47 to
FOGRA51/52 (Refik Telhan)
----------------------------------------------------------------------
Message: 1
Date: Fri, 01 Mar 2019 05:28:24 +0300
From: Refik Telhan <rtelhan(a)ofset.com>
Subject: Re: [ECI-EN] Issues related with the switch from FOGRA39/47
to FOGRA51/52
To: <eci-en(a)lists.callassoftware.com>
Message-ID: <1D1CB34E-5A04-4A2E-ABA3-8CD000D4EC4E(a)ofset.com>
Content-Type: text/plain; charset="utf-8"
Dear Florian,
I am currently working on two related but separate lines.
On the one hand, I am experimenting with different levels of gray axis
correction of the perceptual rendering intent in both FOGRA51 and FOGRA52.
I already have 6 variants of each dataset (Keep Gray Axis set to 0, 3, 4,
5, 7 and 10) generated with Color Toolbox v18 made possible by the generous
help of my colleagues from the local Heidelberg support team.
Interestingly, majority of my colleagues have picked 4 in both datasets.
Now that CoPrA v5 started offering incremental control on the two different
algorithms, namely minimum compression and absolute compression, for the
perceptual rendering intent. CoPrA also enables a two-way control of the
gray balance, you can make it warmer, but you can also make it much cooler.
I am currently generating the variants in the warmer direction. But at this
point I have to underline that fact the kind of gray axis correction Color
Toolbox is making is mostly effective in the lover half of the tonal range.
Apparently, the kind of gray axis
correction done by CoPra is effective through the full range.
The second line is mostly empirical. To retain as much experience as
possible from the FOGRA39L/47L era, I have simply modified the white point
of the FOGRA39L dataset to bring it in line with FOGRA51. As the white
point of FOGRA51 has been measured in M1 mode, to avoid mixing of values
from different measurement mode, I have grabbed the white point of a real
paper in M0 mode that actually hits the FOGRA51 value in M1 mode. The
CIELAB value is 95, 1, -4.5 (M0). Once I find an uncoated stock that
measures 93.5, 2.5, -10 in M1 mode, I will measure it in M0 mode to modify
FOGRA47L.
I have started generating profiles with the modified/revised FOGRA39L
dataset, namely FOGRA39R. As the FOGRA51 compatible proofing substrate that
I am using closely matches this real paper, I hope to have an ink-free
paper white simulation during proofing. As this dataset is holding the same
CMY balance with FOGRA39L, we may even be able to do away with using the
perceptual rendering intent to correct the gray axis.
Under all circumstances, we probably have to focus on getting the total
ink film neutral gray regardless of the paper color (with or without OBA).
The intricate interaction between the UV component of the M1 mode with the
unprinted and the printed paper is probably making things quite complicated
when it comes to stripping of the ink film color from the paper color. This
is why an trying to avoid the M1 measurement mode. I will also be testing
an old i1Pro with a physical UV-cut filter to see how it relates to the
mathematically simulated M2 mode of an i1Pro2. I am still curious about the
reason for the apparent suppression of yellows in all colors. The new
datasets are telling the profiling packages that there is too much yellow.
Hence yellow is being knocked down everywhere. We need the UV component in
the spectro to see and measure the fluorescence in the paper. We probably
have to the read the profiling charts in both M1 and M2 (preferably with a
physical UV-cut filter) m
odes and extract the ink film color by correlating these two datasets.
I will be coming back with more once I finish my planned testing.
Thanks and regards,
--------------------------------------------------------
Refik Telhan, EE B.Sc.
Light and Color Management Consultancy
Aydogdu Sokak 12A, Tarabya Mahallesi
Sariyer, 34457, Istanbul, Turkey
Mobile: + (90) (532) 426 21 87
--------------------------------------------------------
?On 28.02.2019 18:33, "florian(a)suessl.de" <
eci-en-bounces(a)lists.callassoftware.com on behalf of florian(a)suessl.de>
wrote:
??? Dear Refik,
???
????The learning from this very fruitful discussion is, that in the future
(ECI et all) will pay more attention to the gray reproduction of the
perceptual rendering intent.
????
????And for users, the learning is, to switch to perceptual if they are
not pleased with the gamut mapping of rel.col+bpc colour conversions.
???
????Up to FOGRA39 the recommendation (except for newsprint) was the use of
relative colorimetric with black point compensation in order to achieve
better consistency among profile of different profiling packages and to
reduce color deviations of in gamut colours. As you pointed out, there were
no complaints against rel.col+bpc. Athough even in the older FOGRA39/47
days there were and are good reasons for choosing perceptual.
???
????Working on FOGRA51 and 52, we were braking new ground. Along with PSO
Coated v3 and PSO Uncoated v3 several fundamental changes were introduced:
New lighting (UV content), new measurement condition M1, new proofing
substrates with oba content similar that of paper used in production
printing.
????
????Changing several core aspects, there always is a substantial risk of
introducing unexpected side effects ? such as ?cool colors? or as you
mention: unexpected lack of yellow. We (Fogra, ECI) focused on proof to
print precision; i.e. invested a lot of effort, e.g. several printing tests
and the evaluation of more than one characterization data set candidates
(see ECI Fred 15 project). Following the discussion, all of us seem to
agree, that this goal is achieved. And is an important one as a good print
to proof match is the best way to check upfront, whether or not the
resulting colours are ok or not. And to apply changes at the prepress stage
if needed.
???
????You make a very understandable point asking for a bit of continuity
between the FOGRA39L/47L and FOGRA51/52 worlds.
????
????Unfortunately this is *not possible for rel.col+bpc* conversions. By
definition in the ICC standard rel.col is clearly defined ? no way for
tweaking in gamut colours. All we can do is to edit the gray reproduction
of the *perceptual* intent while creating future ECI profiles. Which
probably is, what you mean by saying ?which I think is possible?. Sharing
and discussing the results of your planned tests will be a good basis. So
thanks in advance for your valuable contribution.
???
????
????Best Regards,
??? Florian
???
????> Am 28.02.2019 um 13:08 schrieb Refik Telhan <rtelhan(a)ofset.com>om>:
??? >
????> Dear Claas,
??? >?
????> I haven?t said that there is a problem with the paper white of
FOGRA51 and FOGRA52. In fact, this is the one thing that FOGRA51 and
FOGRA52 got right.
??? >?
????> My objection is to the new CMY balance (which is drastically
different from FOGRA39L and FOGRA47L). What has been working with
FOGRA39L/47L is not working any more.
??? >?
????> Rel.Col does not take the paper color into account, because it is
designed that way. This was also true when we were making FOGRA39
separations. But it was working. The old Rel.Col+BPC conversions created
acceptable grays on real papers loaded with OBA. Why have we lost it?
??? >?
????> If the perceptual rendering intent is not set to do gray axis
correction when the profile is being created, it basically creates the same
CMY balance. And the profiles released by ECI for FOGRA51 and FOGRA52 have
this function switched off. CoPrA5 and Color Toolbox can do this correction
incrimentally. I have already tested different settings in both packages.
But this function has a subjective side. Different people may see the
neutrality at different levels of correction. And this only helps in the
lower half of the tonal range. The main discussion is with the lack of
yellows in the upper half, mid-tones to shadows.
??? >?
????> We are now discussing profiles and datasets for the masses. I am
only asking for a bit of continuity between the FOGRA39L/47L and FOGRA51/52
worlds, which I think is possible.
??? >?
????> Best regards,
??? >?
????> --------------------------------------------------------
??? > Refik Telhan, EE B.Sc.
??? >?
????> Light and Color Management Consultancy
??? >?
????> Aydogdu Sokak 12A, Tarabya Mahallesi
??? > Sariyer, 34457, Istanbul, Turkey
??? >?
????> Mobile: + (90) (532) 426 21 87
??? > --------------------------------------------------------
??? >?
????>?
????> From: <eci-en-bounces(a)lists.callassoftware.com> on behalf of Claas
Bickeb?ller <lists(a)bickeboeller.name>
??? > Reply-To: <eci-en(a)lists.callassoftware.com>
??? > Date: 28 February 2019 Thursday 11:11
??? > To: <eci-en(a)lists.callassoftware.com>
??? > Subject: Re: [ECI-EN] Issues related with the switch from FOGRA39/47
to FOGRA51/52
??? >?
????> Dear Refik,
??? >?
????> again:
??? >?
????> The problem is not the paper white of FOGRA51 or FOGRA52.
??? > It is your, sorry, wrong expectation.
??? >?
????> Relative colorimetric rendering is well defined for in gamut colours.
??? > The chromatic adaptation has to be the Wrong von Kries and
everything has to be mapped relative to the white point.
??? > If you do not like the result, do not use rel.col.
??? >?
????> If you see the same with perceptual, the creator of the
profile/gamut mapping decided to use a white point relative mapping of the
grey axis (which is quite common).
??? > Again, if you do not like it, create a profile with a perceptual
mapping that you like.
??? >?
????> If you have CoPrA 5 try ?absolute compression? and you?ll have the
opposite of rel.col
??? > Then you might see that the ?issue? is related to the gamut mapping
and _not_ the measured values.
??? >?
????> My 2 cents
??? >?
????> Claas
??? >?
????>> Am 28.02.2019 um 00:51 schrieb Refik Telhan <rtelhan(a)ofset.com>om>:
???>>?
????>> Dear Claas,
??? >>?
????>> Yellow is not only a UV-blocker but also a blue-blocker. As it is
initially blocking the incoming UV, the OBA is not triggered at all. So no
secondary blue emission (peak wavelength of the radiation is around 430 nm)
is taking place. Whatever the case is, from a practical standpoint, M0, M1
and M2 measurements of a solid yellow patch produces identical results. Out
of the four primaries, only magenta is letting both the UV and the blue
through. You will have different readings for M0, M1 and M2 readings of a
solid magenta patch. This intricate relationship, between the illuminants
of the spectro, the ink film, the paper as a reflector and the UV-induced
OBA emission, is making things quite complicated.
??? >>?
????>> Probably other spectrometric device manufacturers are also using
similar mathematical techniques to sense and separate the fluorescence from
the paper color. In the end, we actually need to separate the color of
paper from the color of the ink film. To be able to build profiles which
would give us the paper relative colorimetric conversion, we need the color
of the ink film alone not the paper. The combined color is only useful when
we are trying to simulate it in absolute colorimetric terms. What had been
relatively easy or straightforward in the FOGRA39 dataset, probably with
help of the low OBA content of its paper, has become problematic with
FOGRA51 and to a greater extent with FOGRA52. Probably because the way the
measurement data is stripped off the fluorescence and the paper color, the
profiling packages are now thinking that there is an abundance of yellow
color that can be dispensed with.
??? >>?
????>> I have recently tried to generate a high GCR profile from the
FOGRA52 dataset in X-Rite?s i1Profiler. For the input value of L*=a*=b*=0,
the CMYK output for the perceptual rendering intent is C=99.9, M=52, Y=3
(yes, three per cent) and K=91.9, L* out is 29.5 with a*=1.2 and b*=-3.7.
With exactly the same settings, the profile generated out of the FOGRA47L
dataset displays a totally different picture. For L*=a*=b*=0, the CMYK
output is, C=87.5, M=67, Y=50.3 and K=94.9 and L* out is 27.8 with a*=0.3
and b*=-0.9. On real uncoated offset papers with an M0 b* value in the
range of -8 to -10 (in M1 terms the b* can go as down as -15), I find even
the FOGRA47L a bit weak on the yellow side. I have no words to say for the
FOGRA52 conversion. The situation is not as bad as this in the FOGRA51
world, but it still leaves much to be desired. But let me also underline
the fact that this deficiency of yellow is not limited to the gray axis.
This whole issue came to my attention with
a complaint about yellows in the skin tones. The deficiency is
everywhere.
??? >>?
????>> The problem is also not limited to the relative colorimetric
intent. Switching to perceptual in its current form of the profile changes
nothing. The conversions above are perceptual. In the currently released
FOGRA52-based profile gray axis correction is totally switched off. I have
experimented with different levels of gray axis correction with help of
colleagues in the local Heidelberg team using Color Toolbox v19. Using a
halfway setting, a result pleasing to the eye can be achieved. But it only
helps in the lower half of the tonal range, from highlights to mid-tones.
The deficiency in the mid-tone to shadow range still remains unaddressed.
??? >>?
????>> At this point, I must also underline the fact that most of my
objections are based on a comparative analysis between FOGRA39/47 and
FOGRA51/52. The days of the drum scanner were long gone before the
FOGRA39/47 era. We had no issues with the conversions made with these
profiles from the digital images. They only needed a paper white fix.
??? >>?
????>> When duly processed, you would not be able to differentiate drum
scanned images from digitally captured ones. Hence, what was good for the
last ten years can still produce good results with a rather quick paper
white fix.
??? >>?
????>> A printer?s life is already too complicated, let us make it simpler
whenever and wherever possible.
??? >>?
????>> Best regards,
??? >>?
????>> --------------------------------------------------------
??? >> Refik Telhan, EE B.Sc.
??? >>?
????>> Light and Color Management Consultancy
??? >>?
????>> Aydogdu Sokak 12A, Tarabya Mahallesi
??? >> Sariyer, 34457, Istanbul, Turkey
??? >>?
????>> Mobile: + (90) (532) 426 21 87
??? >> --------------------------------------------------------
??? >>?
????>> From: <eci-en-bounces(a)lists.callassoftware.com> on behalf of Claas
Bickeb?ller <lists(a)bickeboeller.name>
??? >> Reply-To: <eci-en(a)lists.callassoftware.com>
??? >> Date: 20 February 2019 Wednesday 12:29
??? >> To: <eci-en(a)lists.callassoftware.com>
??? >> Subject: Re: [ECI-EN] Issues related with the switch from
FOGRA39/47 to FOGRA51/52
??? >>?
????>> Dear Refik,
??? >>?
????>> your findings regarding yellow are not surprising.
??? >> Yellow inks are often blocking (reflecting and absorbing) UV light.
??? >> But the main contribution that you do not see any influence of the
OBA is that yellow filters the blue/purple light that is emitted by the OBA.
??? >>?
????>> The explanation for your findings regarding cyan is that the
emission of the OBA is in the same wavelength area where cyan has the
highest reflection.
??? >> For a typical ink film thickness the fluorescence part of the total
radiance is around only 10% or less for a coated paper.
??? >>?
????>> Also one hint: Be careful when you look at M0 values. They depend
on the instrument you are using.
??? >> In our instruments we get the M0, M1 and M2 values based on a
patented method which first separates the pure reflection from the
fluorescence and then applies the measurement light source (it is not a
filter BTW) mathematically.
??? >> Hence ?our? M0 is the result you?d get from a perfect tungsten lamp
(CIE illuminant A).
??? >> If you use an instrument with a real life tungsten you most
probably get a different result.
??? >>?
????>>?
????>> Regarding the discussion about the grey axis, I can only repeat
what I already commented.
??? >> Relative colorimetric is specified to render the grey axis relative
to the paper white.
??? >> If you do not like the result, use perceptual.
??? >> In general perceptual was the intended RI for image conversions
already when the ICC standard was created.
??? >> From my point of view rel.col. bpc only got popular because older
profiling engines' perceptual mappings changed the image a lot compared to
the RGB original.
??? >> This came, as far as I know, from the fact that these mappings were
based on the experience with images created by a drum scanner where the
original had a very high dynamic range.
??? >> When such a mapping is used for today?s images created by digital
cameras with a much lower dynamic range the result is not ideal/as
expected/as desired whatever you want to call it.
??? >>?
????>> Today?s engines have mapping strategies that are optimized for
today?s image creation scenarios.
??? >>?
????>> So people need to be educated that rel.col bpc is not the best
choice for today?s printing conditions.
??? >>?
????>> So it is not the measurement condition that causes the ?issue? you
see, it is the gamut mapping.
??? >>?
????>> Best regards
??? >>?
????>> Claas?????
????>>?
????>>?
????>>> Am 20.02.2019 um 02:28 schrieb Refik Telhan <rtelhan(a)ofset.com>om>:
??? >>>?
????>>> Dear Florian and All,
??? >>>?
????>>> I have now added a new folder, namely ?2019-02-20?, into the
Dropbox folder that I have shared with some of you. One contains the
roundtrip to PSO Coated v3. And the other is the separation with my
M2-based profile which is then tagged with M1-based profile before coming
back to CIELAB in as>bsolute colorimetric intent.
??? >>>?
????>>> Interestingly, the white point of the M2-measured dataset is 95,
0, 0 (94.819, -0.307, 0.368 to be precise). Apparently, when this
commercially available matt coated paper is ripped off its OBAs it becomes
ideally neutral. The CMY balance of the profile made out of this dataset is
favoring the yellow channel. Yellow channel comes out to be above the
magenta channel, not equal or below.
??? >>>?
????>>> It is all boiling down to the question of what is acceptable as a
visual paper relative neutral gray. FOGRA39 was doing OK. FOGRA47 needed
some yellow boost. We always helped yellows a bit in real life. FOGRA51
definitely needs more yellow. And we have not even started talking about
FOGRA52. I did one heavy GCR version in i1Profiler and ended up with 3% of
yellow at the dark end of the range. I will generate more high GCR versions
of the FOGRA52 dataset with different packages throughout this week.
??? >>>?
????>>> As we are really looking for a paper relative neutrality, we are
in fact targeting the absolute neutrality of the ink film created by the
combination of C-M-Y channels. For this purpose we can leave K alone. In
other words, our mesurements should somehow be stripping off the substrate
color. And OBAs are making things very complicated. I have really started
thinking about the usefulness of M1 measurement mode in measuring color
patches with a yellow coverage. While it is indispensable in assessing the
presence and the amount of OBAs in the uprinted substrate, it gets things
complicated when inks come in the way. Let us not forget that yellow ink is
a UV-cut filter. When yellow is printed on any substrate, no UV radiation
reaches the substrate. Hence, the OBAs receive no excitation. With yellow
ink on top, any substrate with or without OBAs become impervious to UV.
??? >>>?
????>>> As I have made M0, M1 and M2 measurements of the same profiling
chart, let me give you the M0, M1 and M2 results of some critical patches,
??? >>>?
????>>>?
????>>> Solid Yellow Patch
??? >>> #958 C=0 | M=0 | Y=100 | K=0
????>>>?
????>>> M0?????? 86.761, -3.318, 91.430
??? >>> M1?????? 86.751, -3.264, 90.921
??? >>> M2?????? 86.912, -3.412, 92.064
??? >>>?
????>>> Solid Magenta Patch
??? >>> #775 C=0 | M=100 | Y=0 | K=0
??? >>> M0?????? 47.116, 74.537, -3.434
??? >>> M1?????? 47.306, 74.985, -4.176
??? >>> M2?????? 47.400, 74.685, -1.686
??? >>>?
????>>> You can see that the UV radiation from the spectro in M2 mode is
passing through the magenta ink and the secondary blue radiation is coming
back to the sensor.
??? >>>?
????>>> But with the yellow ink, you cannot see any trace of the UV and
the blues (whether reflected or induced). In fact, the yellow ink doing
what it is supposed to do.
??? >>>?
????>>> With cyan the results are intriguing to say the least:
??? >>>?
????>>> #576 C=100 | M=0 | Y=0 | K=0
??? >>> M0?????? 52.341, -35.091, -53.202
??? >>> M1?????? 52.675, -34.902, -53.720
??? >>> M2?????? 52.580, -36.430, -52.034
??? >>>?
????>>> Seeing the limited or no effect of the UV induced blue light in
the solid cyan measurement, I am tempted to say that cyan, being the narrow
band filter that it is, has been blocking the UV coming from the spectro.
??? >>>?
????>>> Simultaneous M0, M1 and M2 measurements of substrates with OBAs
indicate that M0 and M1 results are closer to each then they are to M2
results. Apparently, the M0 illuminant contains some OBA triggering
radiation. May be we should use M2 for a subtrate-free judgement of the ink
film color/neutrality and use M1 for registering the visual appearance. The
spectro is, in a way acting like the human eye, in M1 mode. And may be we
should use an M2-based profile in relative colorimetric (with BPC) or
perceptual mode for seperation/conversion and an M1-based profile for
proofing in absolute colorimetric mode.
??? >>>?
????>>> I am not the color scientist to understand how an M1 mode
measurement set is stripped off the substrate color to serve as a base for
a relative colorimetric conversion, but I am the engineer who can say that
something I wrong in the way data for yellow channel is now being handled.
What has been working for 10+ years with FOGRA39 is now broken, to say the
least.
??? >>>?
????>>> Best regards,
??? >>>?
????>>> --------------------------------------------------------
??? >>> Refik Telhan, EE B.Sc.
??? >>>?
????>>> Light and Color Management Consultancy
??? >>>?
????>>> Aydogdu Sokak 12A, Tarabya Mahallesi
??? >>> Sariyer, 34457, Istanbul, Turkey
??? >>>?
????>>> Mobile: + (90) (532) 426 21 87
??? >>> --------------------------------------------------------
??? >>>?
????>>> ?On 19.02.2019 01:29, "florian(a)suessl.de" <
eci-en-bounces(a)lists.callassoftware.com on behalf of florian(a)suessl.de>
wrote:
??? >>>?
????>>>???? Dear Refik and al,
??? >>>????
????>>>???? nothing to add at that point to your understandable surprising
findings about yellow decrease.
??? >>>????
????>>>???? Regarding your test starting with ?10 LAB GRAY.psd?:
??? >>>???? > Starting with your ?10 LAB GRAY.psd? file, I first did a
RelCol+BPC conversion into ISO Coated v2 (ECI), then assigned PSO coated
v3.
????>>>???? in your scenario the tone values of the conversion to the
?ISO:2003? tvi curve are ?printed? with the ?ISO:2013? curves. The
differences may be not very high, but in order to properly compare the ?v2?
gray reproduction with the current ?v3? reproduction we should take the tvi
differences between the 2003 and 2013 tvi curves into account.
????>>>????
????>>>???? Please feel free to check the files in this dropbox:
??? >>>????
https://www.dropbox.com/s/8kt2kwe1w0vthwj/Gray-comparison_PSOcoated-v3_vers…
??? >>>????
????>>>???? Before reassigning ?PSO Coated v3? to a RelCol+BPC conversion
into ISO Coated v2 (ECI), I applied a tvi correction. Just like in a CtP
system correcting a dot gain deviation on the press. The correction values
are stored in the file ?pdfTB_005_F39_but_F51-tvi.crv? (tv correction done
in the callas PDFToolbox).
??? >>>????
????>>>???? The result is placed next to the RelCol+BPC conversion into
PSO Coated v3. The respective file ?24 Lab Gray relcol+bpc F39 > tvi corr
F51 vs F51? contains both gray reproductions side by side. Switching on
paper simulation in Acrobat Pro and viewing in full screen mode (all bars
and windows hidden), shows a good softproof rendering of the expected
printing result.
??? >>>????
????>>>???? As mentioned earlier also by Jan-Peter Homann, the ?v3?
profile?s linear gradient from paper (here a=2, b=-6) to neutral (a=b=0) is
perceived slightly (too) cold.
??? >>>????
????>>>???? All the best
??? >>>???? Florian
??? >>>????
????>>>???? > Am 18.02.2019 um 22:27 schrieb Refik Telhan <
rtelhan(a)ofset.com>gt;:
??? >>>???? >
????>>>???? > Dear Florian,
??? >>>???? >?
????>>>???? > I have two hats. First of all, I am a prepress guy. But I am
also a printer. On this occasion, I am letting the printer do most of the
talking. For more than 10 years printers have relied on FOGRA39 (and to a
lesser extent on FOGRA47). And they have learnt to cope with the paper
white issue of both datasets. The separations had a full body yellow
channel which they could use to compensate for the daily differences in the
paper white of typically used papers. A solid ink density of 1.30 (ISO E ?
Relative to paper ? polarised) for Yellow was a good starting point, from
which they could manage both the dot gain of the day issues as well as the
paper white differences. They could solve many of the daily problems within
the 1.10 to 1.50 density range.
??? >>>???? >?
????>>>???? > Currently, we are printing on the same paper with
technically the same SIDs for all colors, with the same balance between
C-M-Y channels, but we are now told that we have to print a lesser amount
of yellow. The old profiles were OK from the stand point of the printer.
The only real issue was the yellowish paper white of the proofs. That was
the only thing that needed a fix. Yellow is the carrier of varnish. Varnish
brings gloss, rub resistance and a certain visual depth to black. These are
mostly gone. The old profiles were separating to a paper white of 95, 0, -2
and were doing fine on the real papers. Now the profiles are aware of the
real paper whites that are loaded with OBAs but they offer us less yellow
than before.
??? >>>???? >?
????>>>???? > The leverage yellow was providing is gone. And with FOGRA52
it is even worse. With a high GCR variant of FOGRA52 that I generated
today, I ended up with a separation of C=100, M=52, Y=3 (yes, it is three)
and K=92 at the dark end. With the relatively neutral imaginary paper of
the past, we had sufficient yellow to play around. And the bluer the real
paper is getting the lesser yellow is what we are having. This phenomenon
needs a good explanation.
??? >>>???? >?
????>>>???? > Starting with your ?10 LAB GRAY.psd? file, I first did a
RelCol+BPC conversion into ISO Coated v2 (ECI), then assigned PSO coated
v3. Finally, I did an absolute colorimetric conversion back to Lab. I will
be uploading the file my Dropbox folder under the name ?16 LAB GRAY ?..?.
This is closer to what I need to see. You will also find files with names
starting with 17 and 18. Those are the FOGRA47 and FOGRA52 conversions.
Where the FOGRA47 separation is neeeding more yellow to appear natural to
many eyes, the FOGRA52 is offering less.
??? >>>???? >?
????>>>???? > Paper relative neutrality will always be somewhat
subjective. In both FOGRA51 and 52 worlds, profiles that did gray axis
correction in perceptual conversions midway between a paper relative gray
and an absolute gray, are giving more pleasing results. This, paper
relative neutral gray versus absolute neutral gray issue was with us even
in the old days, especially with the FOGRA47 dataset. We now need it
everywhere.
??? >>>???? >?
????>>>???? > Best,
??? >>>???? >?
????>>>???? > --------------------------------------------------------
??? >>>???? > Refik Telhan, EE B.Sc.
??? >>>???? >?
????>>>???? > Light and Color Management Consultancy
??? >>>???? >?
????>>>???? > Aydogdu Sokak 12A, Tarabya Mahallesi
??? >>>???? > Sariyer, 34457, Istanbul, Turkey
??? >>>???? >?
????>>>???? > Mobile: + (90) (532) 426 21 87
??? >>>???? > --------------------------------------------------------
??? >>>???? >?
????>>>???? >?
????>>>???? > ?On 16.02.2019 20:47, "florian(a)suessl.de" <
eci-en-bounces(a)lists.callassoftware.com on behalf of florian(a)suessl.de>
wrote:
??? >>>???? >?
????>>>???? >???? Dear Refik,
??? >>>???? >????
????>>>???? >???? To test whether or not the yellow reduction causes
problems or is meaningfull, I did another test, you may wish to reproduce:
??? >>>???? >????
????>>>???? >???? - Create a linear gradient from black (LAB 0-0-9) to
white (LAB 100-0-0)
????>>>???? >???? - convert to the two profiles ?v2-300? and ?v3?
(relative colorimetric, black point compensation ON)
??? >>>???? >???? - convert the results back to Lab (absolute colorimetric)
??? >>>???? >???? - check the b values along the gradient from black to
white:
??? >>>???? >????
????>>>???? >???? The v3 version will start with b 0 (neutral) and will
run smoothly to b -6 (paper tone)
??? >>>???? >???? This is the intended behaviour
??? >>>???? >???? And in order to achieve this, obviously yellow needs to
be reduced in dark grays ? otherwise, the gray would be too warm/yellowish
??? >>>???? >????
????>>>???? >???? In other words: the behaviour (cmy percentages) is not
expected and therefore misinterpreted as an error.
??? >>>???? >????
????>>>?? ??>???? This in mind, I would rate the separation behaviour to
be ok.
??? >>>???? >????
????>>>???? >???? For your and other interested parties convenience, I
uploaded my test files for testing here:
??? >>>???? >????
https://www.dropbox.com/s/l1jbob7uemuxxiw/190215%20ECI-EN%20Refik%20yellow%…
??? >>>???? >????
????>>>???? >???? All the best
??? >>>???? >???? Florian
??? >>>???? >????
????>>>???? >???? > Am 15.02.2019 um 23:14 schrieb florian(a)suessl.de:
??? >>>???? >???? >
????>>>???? >???? > Dear Refik,
??? >>>???? >???? >
????>>>???? >???? > Your finding is, that FOGRA39, PSO Coated v2
separations show warmer grays (more yellow) on ?FOGRA51? stock than FOGRA51
separartions printed on the same stock ? each set printed with their
respective tvi curves ? right?
??? >>>???? >???? >
????>>>???? >???? > As we agreed on a very good proof to print match of
FOGRA51, the following test may be used to compare the visual gray
reproductions of PSO Coated v3 (?v3?) and ISO Coated v2 300% (?v2?):
??? >>>???? >???? >
????>>>???? >???? > Assumptions and setup:
??? >>>???? >???? > - both gray reproductions ?v2? and ?v3? printed on
?PSO Coated v3? stock (CIELAB 95 2 -6; M1)
??? >>>???? >???? > - identical CIELab of ink solids for ?2v? and ?v3?
(FOGRA51 values)
??? >>>???? >???? > - each set printed with respective tvi (v2 with
tvi:2003; v3 with tvi:2013)
??? >>>???? >???? > - the visual appearance depends on the cmyk tone
values *measured on print* only.? Lower cmyk values in the file plus higher
tvi in print (?v3?) may result in the same *printed* cmyk tone values as
higher cmyk values in the file plus lower tvi (?v2?).
??? >>>???? >???? > - to achieve the same *printed* tone values for a v3
soft proof, the v2-values must be tone value corrected according to the v3
tone value increase
??? >>>???? >???? > - use of PSO Coated v3, FOGRA51 respectively for
calculating the CIELab values of the two gray reproductions
??? >>>???? >???? >
????>>>???? >???? > step 1: calculate *printed* cmyk values for ?v2?
??? >>>???? >???? > ?print-cmyk v2? (v2-file-cmyk + tvi:3003)????? ??????
????>>>???? >???? > C?????????????? M????????????????????
Y????????????????????? K
??? >>>???? >???? > 38,2?????????????????????? 29???????????????????
30,3???????????????? 11
??? >>>???? >???? > 59,9?????????????????????? 50,6???????????????? 49,4
????????????????45
??? >>>???? >???? > 76,4?????????????????????? 66,5????????????????
64,3???????????????? 79,3
??? >>>???? >???? >
????>>>???? >???? > step 2: calculate v3 file-values to achieve the
printed values of step 1 (v2-file-values + 2003-tvi - 2013-tvi)
??? >>>???? >???? > ?file-cmyk v2>v3? (v2-file-cmyk + tvi:2003 -
2013-tvi)
??? >>>???? >???? > C?????????????? M????????????????????
Y????????????????????? K
??? >>>???? >???? > 25,8????????????????????? 18,9????????????????
19?????????????????? ?6,7
??? >>>???? >???? > 44,2????????????????????? 36,9????????????????
34,9???????????????? 31,2
??? >>>???? >???? > 60,9?????????????????????? 50,5????????????????
48,3???????????????? 64,2
??? >>>???? >???? >
????>>>???? >???? > step 3: create CIELab values; visual appearance of
the
two gray sets ?file-cmyk v3? and ?file-cmyk v2>v3?
??? >>>???? >???? > absolute colorimetric conversion from file-cmyk to
PSO
Coated v3
??? >>>???? >???? > ?file-cmyk v3?
??? >>>???? >???? > L??? a????????? b
??? >>>???? >? ???> 72? 1????????? -5
??? >>>???? >???? > 49? 1????????? -4
??? >>>???? >???? > 28? 1????????? -2
??? >>>???? >???? >
????>>>???? >???? > ?file-cmyk v2>v3?
??? >>>???? >???? > L??? a????????? b
??? >>>???? >???? > 72? 1????????? -4
??? >>>???? >???? > 49? 1????????? -2
??? >>>???? >???? > 27? 0????????? -1
??? >>>???? >???? >
????>>>???? >???? > step 4: visual comparison
??? >>>???? >???? > visual differences (Lab?v3? - Lab?v2>v3?)
??? >>>???? >???? > ?L? ?a??????? ?b
??? >>>???? >??? > 0??? 0????????? -1
??? >>>???? >???? > 0??? 0????????? -2
??? >>>???? >???? > 1??? 1????????? -1
??? >>>???? >???? >
????>>>???? >???? > The negative ?b numbers mean, that relative
colorimetric colour conversions with black point compensation using ?PSO
Coated v3? print slightly more blueish grays than the ?ISO Coated v2 300%?
values.
??? >>>???? >???? >
????>>>???? >???? > Comparing the file-cmky-values gives these results:
??? >>>???? >???? >
????>>>???? >??? ?> ?file-cmyk v2>v3? (v2-file-cmyk + tvi:2003 -
2013-tvi)
??? >>>???? >???? > C?????????????? M????????????????????
Y????????????????????? K
??? >>>???? >???? > 25,8????????????????????? 18,9????????????????
19??????????????????? 6,7
??? >>>???? >???? > 44,2????????????????????? 36,9????????????????
34,9???????????????? 31,2
??? >>>???? >???? > 60,9?????????????????????? 50,5????????????????
48,3???????????????? 64,2
??? >>>???? >???? >
????>>>???? >???? > ?file-cmyk v3?
??? >>>???? >???? > C????????????? ?M????????????????????
Y????????????????????? K
??? >>>???? >???? > 27????????????? 21???????????????????
20??????????????????? 5
??? >>>???? >???? > 46????????????? 38???????????????????
35??????????????????? 28
??? >>>???? >???? > 61????????????? 51???????????????????
44??????????????????? 63
??? >>>???? >???? >
????>>>???? >???? > tv differences *file-tv* (v3 - v2 converted;
tvi:2013)
??? >>>???? >???? > ?C???????????? ?M?????????????????
?Y??????????????????? ?K
??? >>>???? >???? > 1,2???????????? 2,1??????????????????
1,0?????????????????? -1,7
??? >>>???? >???? > 1,8???????????? 1,1??????????????????
0,1?????????????????? -3,2
??? >>>???? >???? > 0,1???????????? 0,5??????????????????
-4,3????????????????? -1,2
??? >>>???? >???? >
????>>>???? >???? > Higher cmy and lower k values are caused by different
black settings
??? >>>???? >???? > The negative tone value difference (-4,3) prooves
your
finding of ?PSO Coatec v3??s higher reduction of yellow in dark gray areas.
????>>>???? >???? >
????>>>???? >???? > However ? in my personal experience I did not see the
kind of blueish turn in grays yet.
??? >>>???? >???? >
????>>>???? >???? > The test was done in Photoshop. Due to rounding
effects the result is not as accurate as it might be, but should be valid.
??? >>>???? >???? >
????>>>???? >???? > All the best
??? >>>???? >???? > Florian
??? >>>???? >???? >
????>>>???? >???? >> Am 15.02.2019 um 13:03 schrieb florian(a)suessl.de:
??? >>>???? >???? >>
????>>>???? > ????>> Dear Refik,
??? >>>???? >???? >>
????>>>???? >???? >> Similar situation at my end:)
??? >>>???? >???? >>
????>>>???? >???? >> Quick answer first:
??? >>>???? >???? >>
????>>>???? >???? >> Comparing the two, I would recommend to choose
profiles with the same TAC setting.
????>>>???? >???? >> As a quick test, reproducing your test with ISO
Coated v2 300%, the comparison of F39 and F51 shows a different picture:
??? >>>???? >???? >>
????>>>???? >???? >> ISO Coated v2 (ECI) ? your figures:
??? >>>???? >???? >> C=29, M=22, Y=22, K=06
??? >>>???? >???? >> C=49, M=40, Y=40, K=27
??? >>>???? >???? >> C=67, M=57, Y=55, K=58
??? >>>???? >???? >>
????>>>???? >???? >> ISO Coated v2 300% (ECI)
??? >>>???? >???? >> C=28, M=21, Y=22, K=07
??? >>>???? >???? >> C=46, M=38, Y=37, K=31
??? >>>???? >???? >> C=62, M=52, Y=50, K=63
??? >>>???? >???? >>
????>>>???? >???? >> PSO Coated v3
??? >>>???? >???? >> C=27, M=21, Y=20, K=05
??? >>>???? >???? >> C=46, M=38, Y=35, K=28
??? >>>???? >???? >> C=61, M=51, Y=44, K=63
??? >>>???? >???? >>
????>>>???? >???? >>
????>>>???? >???? >> Long answer ? comparison of separation values
(cmyk
file):
??? >>>???? >???? >> We talk about differences of some percentages. As
v2
and v3 are based on different tone value curves, I would prefer to take
into account the tvi differences. We talk about differences of some
percentages. You rised the tvi difference already. In addition to that, the
curve shapes are not the same for v2 and v3. As cyan tv is higher than
yellow and magenta, this has some impact.
????>>>???? >???? >> I.o.w. a comparison of tone values should NOT be
based on values in the cmyk files only. We should add the tvi dot gain to
the separation tone value first. As soon as I find the time for this I will
prepare the numbers and come back then.
??? >>>???? >???? >>
????>>>???? >???? >> Another aspect is the Lab result ? quick check by
absolute colorimetric conversion back to Lab:
??? >>>???? >???? >>
????>>>? ???>???? >> ISO Coated v2 300% (ECI)
??? >>>???? >???? >> L=72, a=0, b=-2
??? >>>???? >???? >> L=49, a=0, b=-1
??? >>>???? >???? >> L=27, a=0, b=-1
??? >>>???? >???? >>
????>>>???? >???? >> PSO Coated v3
??? >>>???? >???? >> L=72, a=1, b=-5
??? >>>???? >???? >> L=49, a=1, b=-4
??? >>>???? >???? >> L=28, a=1, b=-2
??? >>>???? >???? >>
????>>>???? >???? >> As expected, the gray Lab values make sense, if
gray
is based on the paper tones 95 0 -2, 95 2 -6, respectively.
??? >>>???? >???? >>
????>>>???? >???? >>
????>>>???? >???? >> All the best for now.
??? >>>???? >???? >> Florian
??? >>>???? >???? >>
????>>>???? >???? >>
????>>>???? >???? >>
????>>>???? >???? >>
????>>>???? >???? >>> Am 15.02.2019 um 11:38 schrieb Refik Telhan
<
rtelhan(a)icloud.com>gt;:
??? >>>???? >???? >>>
????>>>???? >???? >>> Dear Florian,
??? >>>???? >???? >>>
????>>>???? >???? >>> Daily consulting work and a computer breakdown
has
kept me from responding earlier.
??? >>>???? >???? >>>
????>>>???? >???? >>> FOGRA51 and FOGRA52 proofs:
??? >>>???? >???? >>> I agree with the premise that FOGRA51 and
FOGRA52
proofs are a closer match to the real thing (apart from the very dark end
of the shadows, which somewhat hides the inherent purplishness). The real
problem is the conversions/separations made by these profiles. They strip
away a good portion of the yellow channel. And the proofs do a very
realistic simulation of this lack of yellow.
??? >>>???? >???? >>>
????>>>???? >???? >>> FOGRA39/FOGRA47 proofs are unrealistically
yellowish
but the real printing comes out in a more naturally neutral appearance.
Hence, we should focus on the way RGB-to-CMYK conversions are being made.
??? >>>???? >???? >>>
????>>>???? >???? >>> TAC 300
??? >>>???? >???? >>> Comparing the darkest points of FOGRA39 and
FOGRA51-based profiles, I can say that the decision to limit TAC at 300%
has casused a 3 step increase in the L* value of dark end. The Maximum
Black of ISO Coated v2 (ECI) is (9,0,2) whereas PSO Coated v3 can only do
(12,0,5). This quite a loss and is probably related with the 300% TAC.
Latest high reactive UV inks are making TAC values even higher than 330%
possible. But to make color management useable by many, you have decided to
limit the TAC, as it suits conventional oil-based inks more. And, as you
said, experts are free to improvise with higher TACs anyway.
??? >>>???? >???? >>>
????>>>???? >???? >>> Grey Reproduction:
??? >>>???? >???? >>> This is the most problematic part of the issue
at
hand. Even in the FOGRA39 world, no neutral grey is really ?neutral? in the
colorimetric sense of the word. It is all ?relative to paper?. A FOGRA39,
or even a FOGRA47, separation prints with a natural/neutral grey appearance
on its own paper.
??? >>>???? >???? >>>
????>>>???? >???? >>> Let us concentrate on an image that only
contains
three grey steps:
??? >>>???? >??? >>>
????>>>???? >???? >>> Step 1) L*=75, a*=0, b*=0
??? >>>???? >???? >>> Step 2) L*=50, a*=0, b*=0
??? >>>???? >???? >>> Step 3) L*=25, a*=0, b*=0
??? >>>???? >???? >>>
????>>>???? >???? >>> In the ISO Coated v2 (ECI) colorspace these
would
separate into CMYK (under the relative colorimetric rendering intent with
black point compensation) as,
??? >>>???? >???? >>>
????>>>???? >???? >>> C=29, M=22, Y=22, K=06
??? >>>???? >???? >>> C=49, M=40, Y=40, K=27
??? >>>???? >???? >>> C=67, M=57, Y=55, K=58
??? >>>???? >???? >>>
????>>>???? >???? >>> When proofed in a FOGRA39-certified way, these
greys
definitely appear yellowish. But when they are printed on a commercially
available matt coated paper, with a white point of L*=96.0, a*=1.0, b*=-4.6
(MO) --- L*=96.0, a*=1.3, b*=-6.2 (M1) under a C-M-Y dot gain of 14.3% at
mid-tones with the ISO CMYK primaries, we end up with perfectly acceptable
naturally neutral appearance.
??? >>>???? >???? >>>
????>>>???? >???? >>> Then we switch to the FOGRA51 world; the matt
coated
paper is the same, CMYK primaries -in terms paper relative ISO E
(polarized) density values- are almost the same, C-M-Y dot gains are just
1.7% higher than the old system but equal (16%) to each other. However,
with the PSO Coated v3 separation, we end up with,
??? >>>???? >???? >>>
????>>>???? >???? >>> C=27, M=21, Y=20, K=05
??? >>>???? >???? >>> C=46, M=38, Y=35, K=28
??? >>>???? >???? >>> C=61, M=51, Y=44, K=63
??? >>>???? >???? >>>
????>>>???? >???? >>> You can clearly see that the dot percentages
of Cyan
and Magenta have dropped by about 2% which is clearly related with the dot
gain curve rising from 14.3% to 16%. The Black percentage has risen up by
1%, which is in line with the dot gain going down to 16% from 17%. Up to
this this point everything is understandable and accountable.
??? >>>???? >???? >>>
????>>>???? >???? >>> From this point on I feel somewhat lost. The
yellow
channel is bleeding off the charts with no apparent reason. With darker
shades of grey, the gap between Magenta and Yellow gets even bigger. At
L*=5, a*=0, b*=0 the CMYK conversion is C=75, M=63, Y=50, K=89.
??? >>>???? >???? >>>
????>>>???? >???? >>> Technically speaking, under both printing
conditions, the papers are the same, inks are the same, ink film
thicknesses are the same, ink coverages for C, M and K are the same. Why
are we losing the yellow channel?
??? >>>???? >???? >>>
????>>>???? >???? >>> And with FOGRA52, it is pretty much the same
story.
??? >>>???? >???? >>>
????>>>???? >???? >>> To carry over the current balance of the
C-M-Y
separations of the FOGRA39 world into FOGRA51, I have started
playing/experimenting with the white points of the datasets. I first
separated a neutral image into ISO Coated v2 (ECI), assigned PSO Coated v3
to the file and then proofed it in a FOGRA51-verified workflow. As I had
eplained in my previous mail, this gave me a neutral looking proof. The ISO
Coated v2 (ECI) separation and the FOGRA39-certified proof of the same
eciRGBv2 image have a yellowish cast as expected. And the FOGRA51
separation and the FOGRA51-certified proof is on the pinkish/purplish side.
I hope to run a print test next week that includes both FOGRA51 tagged
images receiving ink from the same ink keys. As we have already said, the
FOGRA51-certified proofs are realistic simulations of the actual print.
??? >>>???? >???? >>>
????>>>???? >???? >>> To get rid of the paper color all together, so
that
it does not interfere with the conversion process in any way or form, in
the hope of getting a neutral C-M-Y ink film build up, I have modified the
white point of the FOGRA51 dataset to 95, 0, 0. We have been using
imaginary papers for conversions for a very long time. May be the success
of FOGRA39 and FOGRA47 was in their synthetic paper whites which are very
close to a*=b*=0.
??? >>>???? >???? >>>
????>>>???? >???? >>> I did the editing with ColorLogic?s ColorAnt
v5.1.
After the editing I have also previewed the profiling chart in 2D mode, to
see that all patches have been stripped of the the base paper color. While
checking this new dataset in ColorAnt and later on in CoPrA v4, I have seen
that the profile would go on to be build the with same yellow deficiency.
For some reason, the measurement data was carrying too much yellow.
Consequently, the profiling application is trying too suppress the yellow
to generate a netural grey ink film in the relative colorimetric mode. As I
have discussed recently, the printing conditions of FOGRA39 and FOGRA51 are
very much in parallel. Hence, the balance between C-M-Y channels should in
fact be the same. But they are not acting in the expected way. The only
real difference betwwen the two is the way we are measuring the profiling
charts, namely M0 versus M1.
??? >>>???? >???? >>>
????>>>???? >???? >>> Being an old hand who has lived through the
times
where Rapid Access films were exposed in UV contact frames in ?dark rooms?
illuminated with fluorescent lamps that had yellow sleeves. Those sleeves
were there to block out the UV radiation of the T8 tubes. In short, yellow
filter blocks UV. And for this very reason, yellow ink is UV-killer. Just
try imagining how a spectrophotometer, with its 45?/0? geometry, is sending
the illumination to the measured sample. In M1 measurement mode, the
unobstructed UV ligh,t that is now part of the illumination, easily reaches
the unprinted paper. Hence, OBA is triggered to create the secondary
radiation that is centered around 430 nanometers. We then measure this as a
lower b* value. With a moderate amount of OBA, the b* value typically moves
from -4.5 to -6. Now let us print yellow ink on this paper. When you
measure a patch which contains a heavy dose of yellow ink, the UV
illuminant of the spectrophotometer never r
eaches the paper. The higher the dot percent of yellow ink, higher is the
filtering effect. Hence, areas covered with yellow ink will never release
the secondary blue radiation. But the software, most probably, thinking
that it is there, and based on the ?normal? level of b* value, is assuming
that an extra amount yellow has been used to neutralizing this blue
component. Consequently, the software, while doing a relative conversion,
is stripping off the supposedly ?extra? yellow from the separation. Just do
an absolute colorimetric conversion and see how much yellow ii added to the
yellow channel to counter the bluness of the paper. And the suppression
grows as the coverage/thickness of yellow ink increases. The more you have
the yellow ink, the more it blocks the UV LED of the spectro.
??? >>>???? >???? >>>
????>>>???? >???? >>> Under these circumstaces, I would say that M1
measurement mode has created more problems than it was designed to solve.
While it may be a handy tool to see the amount of OBA contained in the
print substrate, it is simply misleading when yellow ink is around. Just do
a series of measurements at the same spot without moving the spectro in M0,
M1 and M2 modes, you will have very healty indication of the existence and
the amount of OBA. But let us not forget yellow filters are UV-killers. And
yellow ink is a yellow filter.
??? >>>???? >???? >>>
????>>>???? >???? >>> Having graduated as an electrical engineer 42
years
ago, I have lived through the heyday of fluroscent lamps but I always hated
the rate at which the blue output decays. The T8 tubes being rated at 20000
hours for daily use can only last 2500 hours as a reference. After that,
they are only for good for general illumination. And now LED light sources
are becoming full-spectrum illuminants, and some have reached very high CRI
values (98+) at 5000?K. There manufackurers are now desparately trying to
mix and match them UV chips to reach ISO 3664:2009 compatibility.
??? >>>???? >???? >>>
????>>>???? >???? >>> Fluorescent lamps are on their way out,
leaving the
general public with no source of UV other than the Sun itself. And nobody
would be reading a book in full color under the Sun. Hence, the paper
industry has to reconsider the way they are using OBAs now. LED light
sources, even the full-spectrum white LEDs, do not contain any UV. They
ususally cut emission atf 410 ? 420 nanometers. White LEDs are typically
triggered with a blue emitting diode evidenced by the peak at 410
nanometers. I have not made any testing to see which wavelengths actually
trigger the OBAs, I would leave this to good scientists. But apparently, we
should get ready for a UV-free and OBA-free eco system, where we would not
need to use the M1 measuring mode. In some years time, the illumination for
the public will become UV-free. It is high time that we start getting rid
of UV (as illuminant) related technologies and problems. As an ink-curing
tool, I believe that it will become indisp
ensible.
??? >>>???? >???? >>>
????>>>???? >???? >>> Many of what I said is just hypothesis. I
believe
there very good color scientists who can take over and do the rest.
??? >>>???? >???? >>>
????>>>???? >???? >>> Looking forward to hearing from my colleagues,
I
remain.
??? >>>???? >???? >>>
????>>>???? >???? >>> Best regards,
??? >>>???? >???? >>>
????>>>???? >???? >>>
--------------------------------------------------------
??? >>>???? >???? >>> Refik Telhan, EE B.Sc.
??? >>>???? >???? >>>
????>>>???? >???? >>> Light and Color Management Consultancy
??? >>>???? >???? >>>
????>>>???? >???? >>> Aydogdu Sokak 12A, Tarabya Mahallesi
??? >>>???? >???? >>> Sariyer, 34457, Istanbul, Turkey
??? >>>???? >???? >>>
????>>>???? >???? >>> Mobile: + (90) (532) 426 21 87
??? >>>???? >???? >>> e-Mail: rtelhan(a)icloud.com
??? >>>???? >???? >>>
--------------------------------------------------------
??? >>>???? >???? >>>
????>>>???? >???? >>> P.S. Just to find a short term solution to
the
problem, I have modified the FOGRA39L dataset to bring it along side the
PC1 printing condition. Using ColorAnt v5, I have modified the white point
to 95, 1.5, -6 (which is in fact an M1 measurement, but perhaps I should
have used the M0 value of the same paper, namely 96, 1, -4.5). I have then
edited the tone values to ISO 2013 Curve A. The profile (TAC: 330%)
generated out of this heavily modified dataset is acting in much the way
that I expected:
??? >>>???? >???? >>>
????>>>???? >???? >>> (RelCol w/BPC conversion)
??? >>>???? >???? >>>
????>>>???? >???? >>> L*=75, a*=0, b*=0 ----> C=27, M=19, Y=20,
K=06
??? >>>???? >???? >>> L*=50, a*=0, b*=0 ----> C=42, M=32, Y=33,
K=36
??? >>>???? >???? >>> L*=25, a*=0, b*=0 ----> C=52, M=42, Y=40,
K=72
??? >>>???? >???? >>>
????>>>???? >???? >>> I will be first doing some image conversions
and
FOGRA51-verified/certified proofing to see how naturally looking CMYK files
I am getting. And then I will do a machine test to see how close I can get
to the proofs. I will definitely share the results.
??? >>>???? >???? >>>
????>>>???? >???? >>> -----------------------------
??? >>>???? >???? >>>
????>>>???? >???? >>> ?On 12.02.2019 14:29,
"florian(a)suessl.de" <
eci-en-bounces(a)lists.callassoftware.com on behalf of florian(a)suessl.de>
wrote:
??? >>>???? >???? >>>
????>>>???? >???? >>>?? Dear Rafik,
??? >>>???? >???? >>>
????>>>???? >???? >>>?? Thanks again for your valuable posts.
??? >>>???? >???? >>>
????>>>???? >???? >>>?? Regarding your findings about FOGRA51 and
FOGRA52
proofs:
??? >>>???? >???? >>>?? Comparing with FOGRA39 proofs, which tend to
show
warmer colours I agree. And I can imagine that ?cooler? F51 and F52? proofs
are confusing for clients who are familiar with ?warmer? FOGRA39 proofs.
BUT:
??? >>>???? >???? >>>?? As Claas already mentioned, the proof to
print
match is by far better with FOGRA51 and FOGRA52 under proper lighting
conditions (with proper UV content; ISO3664:2009). Especially regarding
light colours and paper simulation which was by far too yellowish/warm in
F39/ F47 proofs compared to standard compliant printing on todays papers.
??? >>>???? >???? >>>
????>>>???? >???? >>>?? TAC 300
??? >>>???? >???? >>>?? The reason for reducing TAC to 300 and not
to
offer two flavours as for FOGRA39: In general, TAC 300% work well with
regard to the visual result. More than 300% in some cases (paper dependant)
may cause production issues. Second reason: Providing one profile makes it
easier for the non skilled users to choose the right profile per paper
type. This to reflect one of the main goals of the ECI: Making colour
management easier to use.
??? >>>???? >???? >>>?? Of course experts are free to create and
use
profilles with other TAC and separation settings, as they have to tools and
expertise.
????>>>???? >???? >>>?? For these reasons, we (ECI) decided to
provide
only one profile with TAC 300%.
????>>>???? >???? >>>
????>>>???? >???? >>>?? Grey reproduction:
??? >>>???? >???? >>>?? This topic is very tricky and cannot be
solved
perfectly with a single profile, a single grey reproduction respectively.
The chromatic white point adaptation of our colour perception depends on
the given white reference when we look at the print. This reference changes
from situation to situation. In many cases, the paper white is a good
choice, given, there is nothing else viewed influencing the white
adadaption to the paper, and given, the illumination is perceived ?white?.
??? >>>???? >???? >>>
????>>>???? >???? >>>?? As soon as more than one reference white is
viewed
simultaneously, it becomes difficult. For example in magazine production,
with different stock for cover and content. In case of an ad which is split
in two halfs, one printed on the cover paper (coated, OBA content), the
other half printed on SC paper (low to no OBA).
????>>>???? >???? >>>?? Each part colour separated with the
respective
profile, may show different grey reproductions which work well if viewed
exclusively ? but may not if viewed simultaneously.
????>>>???? >???? >>>?? I.o.w.: When creating the profiles, it is
not
possible to take into account all variables influencing the grey
perception. There is no digital right or wrong.
??? >>>???? >???? >>>?? If problems e.g. in above mentioned
situations
(one product, different papers) occure, editing the grey axis will be
depend on a case by case decision ? as you already mentioned.? ?Standard?
profiles can provide one grey reproduction which may or may not work in a
given situation.
??? >>>???? >???? >>>
????>>>???? >???? >>>
????>>>???? >???? >>>?? Best Regards
??? >>>???? >???? >>>?? Florian S??l
??? >>>???? >???? >>>
????>>>???? >???? >>>> Am 12.02.2019 um 01:14 schrieb Refik
Telhan <
rtelhan(a)ofset.com>gt;:
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Dear Florian,
??? >>>???? >???? >>>>
????>>>???? >???? >>>> I agree, yellow can add very little to
the
darkening of the L* value of the shadows. But, due to the optical and
physical qualities of the varnish that it contains, yellow ink adds to the
blackness ?visually?. You may not be able to ?measure? it but you can
definitely ?see? it. The gloss effect of this ink definitely add to the
apparent blackness of the shadows. It is no wonder that the computer
display and tv manufacturer are usin using very glossy panels to increase
the apparent dynamic range of the monitor. Any mattness casuses surface
scatter and reduces visual darkness. Furthermore, the yellow ink also
physically protects the printed image against rub resistance.
??? >>>???? >???? >>>>
????>>>???? >???? >>>> As TAC has been reduced down to 300% in
FOGRA51 as
opposed to its value of 330% in FOGRA39, yellow loses additional strength.
We end up with bluish cold blacks which may prove to be problematic in
printing art books. In some cases the artwork may call for a dark reddish
or a brownish shadow. But the current profiles are making it very hard to
get there. You need to heavily modify the RGB shadows before the conversion
to CMYK.
??? >>>???? >???? >>>>
????>>>???? >???? >>>> And this only one side of the story. As
the new
datasets (both FOGRA51 and FOGRA52) are based on ?real? papers, the
paper-relative greys of the relative colorimetric (with BPC) and the
perceptual rendering intent conversions are leaving much to be desired. The
paper-relative neutrals rely too much on the chromatic adaptation
capability of the eye. The paper-white-simulated proofs move away from the
balanced appearance of the RGB (any RGB) version. Color ToolBox is equipped
with the Keep Grey Axis functionality (which you can adjust from
paper-relative grey to absolute-netural grey in 10 steps) that allows you
to compensate for the paper color in the perceptual rendering intent
conversions.
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Best regards,
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Refik Telhan, EE B.Sc.
??? >>>???? >???? >>>> Light and Color Management Consultancy
??? >>>???? >???? >>>>
????>>>???? >???? >>>> From:
<eci-en-bounces(a)lists.callassoftware.com> on
behalf of Florian S??l <florian(a)suessl.de>
??? >>>???? >???? >>>> Reply-To:
<eci-en(a)lists.callassoftware.com>
??? >>>???? >???? >>>> Date: 11 February 2019 Monday 20:19
??? >>>???? >???? >>>> To:
<eci-en(a)lists.callassoftware.com>
??? >>>???? >???? >>>> Subject: Re: [ECI-EN] Issues related with
the
switch from FOGRA39/47 to FOGRA51/52
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Dear Refik,
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Thank very much for your extensive testing
and the
documentation of your findings.
??? >>>???? >???? >>>>
????>>>???? >???? >>>> With regard to dark grey tones, the
decrease of
yellow tone values is intended as the the following may explain:
??? >>>???? >???? >>>>
????>>>???? >???? >>>> According to the standard printing ink
sequence,
yellow is the last ink (kcmy sequence).
??? >>>???? >???? >>>> The expected effect of raising ink tone
values is
that higher values cause darker colour.
??? >>>???? >???? >>>> But this is not true.
??? >>>???? >???? >>>> Printed on top of the other inks, the
yellow ink
tends to behave like a mirror, reflecting light. In order to avoid this
effect, yellow is limited in dark grey tones.
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Hope this helps.
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Best Regards
??? >>>???? >???? >>>> Florian S??l
??? >>>???? >???? >>>> Vice chairman of the ECI
??? >>>???? >???? >>>> --
??? >>>???? >???? >>>> Florian S??l
??? >>>???? >???? >>>> Go?lerstra?e 29
??? >>>???? >???? >>>> 12161 Berlin
??? >>>???? >???? >>>>
????>>>???? >???? >>>> Am 11.02.2019 um 09:47 schrieb Refik
Telhan <
rtelhan(a)ofset.com>gt;:
??? >>>???? >???? >>>>
????>>>???? >???? >>>>> Dear Colleagues,
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> It all started with a question raised
by Mr.
Martin Orpen in his mail dated 22.08.2018 on the colorsync-users list.
There was then almost a week long discussion with an open end.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> From that point on, I have made
several
conversions using FOGRA39, FOGRA47, FOGRA51 and FOGRA52 based profiles. At
some point I have started generating profiles with the FOGRA51 and FOGRA52
datasets in multiple profiling software applications with different
settings to have a better understanding on what is going on.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Mr. Orpen?s original complaint was the
lack of
yellow in skin tones with conversions made with PSO Coated v3. But when I
started doing conversions using this profile, I have ended seeing that that
deficiency ih yellow is widespread. Furthermore, what was true for FOGRA51
was also true for FOGRA52-based profiles.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> To simplify the matter, I have created
a Photoshop
file in L*a*b* color mode that contained a linear gradient from L*=0 ? a*=0
? b*=0 to? L*=100 ? a*=0 ? b*=0. I have placed 10 color sampler points to
L*= 5, 15, 25, 35, 45, 55, 65, 75, 85 and 95, to keep track of their
changes. I then converted this file into ?eciRGB v2? color space. The RGB
values at these points came out to be R=G=B=13, 37, 64, 90, 114, 140, 165,
190, 216 and 242, respectively.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Starting with this neutral grey RGB
gradient, I
have done (relative colorimetric with black point compensation) conversions
into FOGRA39 using ISO Coated v2 (ECI), into FOGRA51 using PSO Coated v3,
into FOGRA47 using PSO Uncoated 12647 (ECI) and into FOGRA52 using PSO
Uncoated v3. Below are the CMYK percentages for each of the 10 spots.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> FOGRA39 conversion:
??? >>>???? >???? >>>>> #01 / L*=05 a*=0 b*=0 / C=81 M=72 Y=65
K=85
??? >>>???? >???? >>>>> #02 / L*=15 a*=0 b*=0 / C=75 M=65 Y=61
K=73
??? >>>???? >???? >>>>> #03 / L*=25 a*=0 b*=0 / C=67 M=57 Y=55
K=58
??? >>>???? >???? >>>>> #04 / L*=35 a*=0 b*=0 / C=60 M=50 Y=49
K=44
??? >>>???? >???? >>>>> #05 / L*=45 a*=0 b*=0 / C=53 M=44 Y=43
K=33
??? >>>???? >???? >>>>> #06 / L*=55 a*=0 b*=0 / C=46 M=37 Y=36
K=22
??? >>>???? >???? >>>>> #07 / L*=65 a*=0 b*=0 / C=38 M=29 Y=30
K=13
??? >>>???? >???? >>>>> #08 / L*=75 a*=0 b*=0 / C=29 M=22 Y=23
K=06
??? >>>???? >???? >>>>> #09 / L*=85 a*=0 b*=0 / C=19 M=13 Y=13
K=02
??? >>>???? >???? >>>>> #10 / L*=95 a*=0 b*=0 / C=07 M=05 Y=05
K=00
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> FOGRA51 conversion:
??? >>>???? >???? >>>>> #01 / L*=05 a*=0 b*=0 / C=75 M=63 Y=50
K=89
??? >>>???? >???? >>>>> #02 / L*=15 a*=0 b*=0 / C=67 M=57 Y=47
K=77
??? >>>???? >???? >>>>> #03 / L*=25 a*=0 b*=0 / C=61 M=51 Y=44
K=62
??? >>>???? >???? >>>>> #04 / L*=35 a*=0 b*=0 / C=55 M=46 Y=40
K=48
??? >>>???? >???? >>>>> #05 / L*=45 a*=0 b*=0 / C=50 M=42 Y=37
K=35
??? >>>???? >???? >>>>> #06 / L*=55 a*=0 b*=0 / C=43 M=35 Y=32
K=22
??? >>>???? >???? >>>>> #07 / L*=65 a*=0 b*=0 / C=36 M=28 Y=26
K=12
??? >>>???? >???? >>>>> #08 / L*=75 a*=0 b*=0 / C=27 M=21 Y=20
K=05
??? >>>???? >???? >>>>> #09 / L*=85 a*=0 b*=0 / C=18 M=13 Y=13
K=01
??? >>>???? >???? >>>>> #10 / L*=95 a*=0 b*=0 / C=06 M=05 Y=04
K=00
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> As you can see, the same color is
converted into a
different C-M-Y balance as the L* value goes lower with the FOGRA51
conversion. On the other hand, the C-M-Y balance is kept steady till the
very dark shadows in FOGRA39. As the CMYK primaries are pretty much the
same on both sides and the TVI curves, though different by about 1.7%, have
the same C-M-Y balance, I cannot see any reason for the drop in Y as we go
down the L* axis.
??? >>>???? > ????>>>>>
????>>>???? >???? >>>>> The situation is almost the same with
FOGRA47 and
FOGRA52.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> FOGRA47 conversion:
??? >>>???? >???? >>>>> #01 / L*=05 a*=0 b*=0 / C=81 M=62 Y=54
K=90
??? >>>???? >???? >>>>> #02 / L*=15 a*=0 b*=0 / C=75 M=59 Y=52
K=80
??? >>>???? >???? >>>>> #03 / L*=25 a*=0 b*=0 / C=65 M=53 Y=47
K=64
??? >>>???? >???? >>>>> #04 / L*=35 a*=0 b*=0 / C=58 M=48 Y=44
K=46
??? >>>???? >???? >>>>> #05 / L*=45 a*=0 b*=0 / C=49 M=40 Y=36
K=36
??? >>>? ???>???? >>>>> #06 / L*=55 a*=0 b*=0 / C=38 M=30 Y=28
K=27
??? >>>???? >???? >>>>> #07 / L*=65 a*=0 b*=0 / C=29 M=21 Y=20
K=20
??? >>>???? >???? >>>>> #08 / L*=75 a*=0 b*=0 / C=20 M=15 Y=14
K=14
??? >>>???? >???? >>>>> #09 / L*=85 a*=0 b*=0 / C=12 M=08 Y=08
K=08
??? >>>???? >???? >>>>> #10 / L*=95 a*=0 b*=0 / C=04 M=03 Y=03
K=02
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> FOGRA52 conversion:
??? >>>???? >???? >>>>> #01 / L*=05 a*=0 b*=0 / C=85 M=62 Y=42
K=88
??? >>>???? >???? >>>>> #02 / L*=15 a*=0 b*=0 / C=76 M=58 Y=43
K=78
??? >>>???? >???? >>>>> #03 / L*=25 a*=0 b*=0 / C=66 M=54 Y=39
K=61
??? >>>???? >???? >>>>> #04 / L*=35 a*=0 b*=0 / C=58 M=47 Y=36
K=43
??? >>>???? >???? >>>>> #05 / L*=45 a*=0 b*=0 / C=49 M=40 Y=33
K=28
??? >>>???? >???? >>>>> #06 / L*=55 a*=0 b*=0 / C=40 M=32 Y=28
K=16
??? >>>???? >???? >>>>> #07 / L*=65 a*=0 b*=0 / C=33 M=25 Y=22
K=08
??? >>>???? >???? >>>>> #08 / L*=75 a*=0 b*=0 / C=24 M=17 Y=16
K=03
??? >>>???? >???? >>>>> #09 / L*=85 a*=0 b*=0 / C=15 M=10 Y=10
K=01
??? >>>???? >???? >>>>> #10 / L*=95 a*=0 b*=0 / C=05 M=03 Y=03
K=00
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> To approach the situation from another
angle, I
have also converted the same neutral grey RGB file into GRACoL2006 and
GRACoL 2013 to see have how they perform under the same conditions. Here
are the results:
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> GRACoL2006_Coated1v2 conversion:
??? >>>???? >???? >>>>> #01 / L*=05 a*=0 b*=0 / C=83 M=75 Y=71
K=87
??? >>>???? >???? >>>>> #02 / L*=15 a*=0 b*=0 / C=80 M=73 Y=70
K=69
??? >>>???? >???? >>>>> #03 / L*=25 a*=0 b*=0 / C=73 M=65 Y=64
K=49
??? >>>???? >???? >>>>> #04 / L*=35 a*=0 b*=0 / C=64 M=55 Y=55
K=34
??? >>>???? >???? >>>>> #05 / L*=45 a*=0 b*=0 / C=56 M=47 Y=47
K=23
??? >>>???? >???? >>>>> #06 / L*=55 a*=0 b*=0 / C=49 M=40 Y=40
K=12
??? >>>???? >???? >>>>> #07 / L*=65 a*=0 b*=0 / C=41 M=32 Y=33
K=04
??? >>>???? >???? >>>>> #08 / L*=75 a*=0 b*=0 / C=31 M=24 Y=24
K=00
??? >>>???? >???? >>>>> #09 / L*=85 a*=0 b*=0 / C=19 M=13 Y=14
K=00
??? >>>???? >???? >>>>> #10 / L*=95 a*=0 b*=0 / C=06 M=04 Y=05
K=00
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> GRACoL20013_CRPC6 conversion:
??? >>>???? >???? >>>>> #01 / L*=05 a*=0 b*=0 / C=80 M=71 Y=62
K=90
??? >>>???? >???? >>>>> #02 / L*=15 a*=0 b*=0 / C=75 M=67 Y=62
K=75
??? >>>???? >???? >>>>> #03 / L*=25 a*=0 b*=0 / C=69 M=60 Y=57
K=55
??? >>>???? >???? >>>>> #04 / L*=35 a*=0 b*=0 / C=62 M=53 Y=51
K=38
??? >>>???? >???? >>>>> #05 / L*=45 a*=0 b*=0 / C=55 M=46 Y=44
K=25
??? >>>???? >???? >>>>> #06 / L*=55 a*=0 b*=0 / C=46 M=38 Y=37
K=16
??? >>>???? >???? >>>>> #07 / L*=65 a*=0 b*=0 / C=39 M=30 Y=29
K=07
??? >>>???? >???? >>>>> #08 / L*=75 a*=0 b*=0 / C=30 M=23 Y=22
K=02
??? >>>???? >???? >>>>> #09 / L*=85 a*=0 b*=0 / C=18 M=13 Y=13
K=00
??? >>>???? >???? >>>>> #10 / L*=95 a*=0 b*=0 / C=06 M=04 Y=04
K=00
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Although the paper white of GRACoL2013
is now in
line with 12647-2:2013, it does separate RGB into a C-M-Y balance very
similar to GRACoL2006.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Extreme loss of yellow ink in areas
mid-tone and
upwards has many negative side effects. Rich blacks are bluish/purplish and
many clients do not like that. Yellow ink typically prints last for a good
reason. It contains varnishes that give the image extra gloss and rub
resistance. It is also the least tacky of the inks. Hence, by reducing its
amount in the separation causes even less yellow ink being transferred to
paper. Wet on wet printing sometimes requires more of the final ink to be
properly transferred not less.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> To get round this problem I have
tried
recalculating the profiles to get some grey axis correction when converting
with perceptual rendering intent. The old ProfileMaker v5, CoPrA v4 and
Color Toolbox v18 (with incremental control) all have the tools to
compensate for the color of paper. Interestingly this feature does help in
the highlight to mid-tone range but not in the mid-tone to shadow range.
????>>>???? >???? >>>>>
????>>>???? >???? >>>>> On a recent occasion, I have also
witnessed the
fact that inkjet contract proofs are not good in simulating the inherent
shift towards blue/purple in the shadows. What may appear as a neutral
shadow on a certified proof is printed with a blue/purple cast, which may
not be visually acceptable the client.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> This problem needs to be addressed.
Doing a
conversion in Photoshop using a relative colorimetric or a perceptual
rendering intent is quite misleading without switching on the Proof Color
View with paper white simulation. You can only see the overall loss of
yellow when you activate soft proofing. Given that Photoshop still leaves
much to be desired in terms of soft proofing, especially with uncoated
papers, you can only use verified/certified inkjet proofs to see the actual
result of your RGB to CMYK conversion.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> While FOGRA39 and FOGRA47 do share an
imaginary
paper white (95,0,2), being close to a*=0 + b*=0, the conversions made by
both profiles maintain some kind of paper relative neutrality. Even if the
paper white simulated absolute colorimetric proofs are not precisely
matching any real print substrate, we had over the years developed
chromatic adaptation skills that would bridge the gap. While the prepress
process is rather smooth with FOGRA39, bridging the gap between the
contract proof and the real substrate has always been the problematic side.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> But with FOGRA51 (and as a matter of
fact, for the
same reason, with FOGRA52) prepress and proofing needs heavy tweaking after
RGB to CMYK conversion to introduce some of the lost yellow back to the
scene. If not done properly, a proof to print match is tricky especially if
you have heavy areas in the image. Hence, the process as a whole became
problematic.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Dear colleagues, I invite you to shed
some light
on this in mystery.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Best regards,
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Refik Telhan, EE B.Sc.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Light and Color Management
Consultancy
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Aydogdu Sokak 12A, Tarabya Mahallesi
??? >>>???? >???? >>>>> Sariyer, 34457, Istanbul, Turkey
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> Mobile: + (90) (532) 426 21 87
??? >>>???? >???? >>>>> e-Mail: rtelhan(a)ofset.com
rtelhan(a)icloud.com
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>> P.S. The following link will let you
download a
PDF that contains screen shots of the above conversions. There are also
four screen shots from the interface of CoPra 5, showing that the problem
is related with the measurement data sets and not with the profiles
calculated by Color Toolbox.
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>>
https://www.dropbox.com/s/vqdjezncf8l60cq/FOGRA_Conversions.pdf?dl=0
??? >>>???? >???? >>>>>
????>>>???? >???? >>>>>
????>>>???? >???? >>>>>
????>>>???? >???? >>>>>
????>>>???? >???? >>>>>
????>>>???? >???? >>>>>
_______________________________________________
??? >>>???? >???? >>>>> ECI-EN mailing list
??? >>>???? >???? >>>>> ECI-EN(a)lists.callassoftware.com
??? >>>???? >???? >>>>>
http://lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>???? >???? >>>>
_______________________________________________
ECI-EN mailing list ECI-EN@lists.callassoftware.comhttp://
lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>???? >???? >>>>
_______________________________________________
??? >>>???? >???? >>>> ECI-EN mailing list
??? >>>???? >???? >>>> ECI-EN(a)lists.callassoftware.com
??? >>>???? >???? >>>>
http://lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>???? >???? >>>
????>>>???? >???? >>>?? --
??? >>>???? >???? >>>?? Florian S??l
??? >>>???? >???? >>>?? Go?lerstra?e 29
??? >>>???? >???? >>>?? 12161 Berlin
??? >>>???? >???? >>>?? +49 172 3091154
??? >>>???? >???? >>>
????>>>???? >???? >>>??
_______________________________________________
???>>>???? >???? >>>?? ECI-EN mailing list
??? >>>???? >???? >>>?? ECI-EN(a)lists.callassoftware.com
??? >>>???? >???? >>>??
http://lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>???? >???? >>>
????>>>???? >???? >>>
_______________________________________________
??? >>>???? >???? >>> ECI-EN mailing list
??? >>>???? >???? >>> ECI-EN(a)lists.callassoftware.com
??? >>>???? >???? >>>
http://lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>???? >???? >>
????>>>???? >???? >> --
??? >>>???? >???? >> Florian S??l
??? >>>???? >???? >> Go?lerstra?e 29
??? >>>???? >???? >> 12161 Berlin
??? >>>???? >???? >> +49 172 3091154
??? >>>???? >???? >>
????>>>???? >???? >
????>>>???? >???? > --
??? >>>???? > ????> Florian S??l
??? >>>???? >???? > Go?lerstra?e 29
??? >>>???? >???? > 12161 Berlin
??? >>>???? >???? > +49 172 3091154
??? >>>???? >???? >
????>>>???? >????
????>>>???? >???? --
??? >>>???? >???? Florian S??l
??? >>>???? >???? Go?lerstra?e 29
??? >>>???? >???? 12161 Berlin
??? >>>???? >???? +49 172 3091154
??? >>>???? >????
????>>>???? >???? _______________________________________________
??? >>>???? >???? ECI-EN mailing list
??? >>>???? >???? ECI-EN(a)lists.callassoftware.com
??? >>>???? >????
http://lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>???? >????
????>>>???? > _______________________________________________
??? >>>???? > ECI-EN mailing list
??? >>>???? > ECI-EN(a)lists.callassoftware.com
??? >>>???? >
http://lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>????
????>>>???? --
??? >>>???? Florian S??l
??? >>>???? Go?lerstra?e 29
??? >>>???? 12161 Berlin
??? >>>???? +49 172 3091154
??? >>>????
????>>>???? _______________________________________________
??? >>>???? ECI-EN mailing list
??? >>>???? ECI-EN(a)lists.callassoftware.com
??? >>>????
http://lists.callassoftware.com/mailman/listinfo/eci-en
??? >>>????
????>>> _______________________________________________
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??? >>> ECI-EN(a)lists.callassoftware.com
??? >>>
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??? >>?
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???
????--
??? Florian S??l
??? Go?lerstra?e 29
??? 12161 Berlin
??? +49 172 3091154
???
????_______________________________________________
??? ECI-EN mailing list
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