Thanks for the questions and the interest!
Answer below for:
2. Re: Total Ink Coverage with GCR based on what? (Henk Gianotten)
I put numbers in front of Henks questions:
1. >Nice figures but it's good to know how the CMYK combinations were created.
2. >Maximum K of 100%?
3. "Dark Red" in newsprint 244% with still cyan in it
instead of K?
4. >Or in other words how long
and how wide are the GCR settings for these
profiles?
5. >Henk (Partly gray and no gray
component replacement!)
-----------------------------------------------------------------------------------
Henk Gianotten, Prins Hendriklaan 58 3761 DW Soest, Netherlands
Tel. +31 (0)35 60 12 206 Fax: +31 (0)84 73 04 497 e-mail: henk(a)gianotten.com
------------------------------------------------------------------------------------
1. Yes the figures are nice indeed. The printers, the CEO's and bookbinders are very
happy!
The figures where created in the software we use and it looks for a Lab match that has the
lowest amount of ink: for each colour (not a compromise calculation as in normal
ICC-profile with a static GCR and TIC).
2. Maximum K normally end up around 96% or 97%. I can not alter this, it is based on the
measurement. I have a theory reg the maximum % in the inks:
If you have measured thousands of prints and tone scales (in offset) and especially for
poor paper qualities it is always the same: vaules around 97% have a higher density then
100%. My theory is that the plate carry more ink where there are small
"openings" due to the capillary attraction. Can't think of any other reason.
In other words: 97% yellow is more yellow than 100%.
3. The example I gave for a "dark red" you commented on was not for newsprint.
It was for coated offset. In newsprint a deep saturated colour, like for example red,
usually get a TIC around 205% to 209%: but as said, a neutral black in the same print can
have a TIC around 180% (and still darker then the values from ISOnewspaper26v4, we usually
print a L at 38 to 39 and not 42).
Probably no cyan at all in this "dark red": a cyan in red would lower the
saturation of the red: cyan is a enemy to red.
I am sure you have seen that with a well known german ICC-profiling software that they
have a problem to keep out colour deviations in the dark saturated shadows: I see far to
often prints where a saturated red jacket is gray in the shadows because of cyan: ugly and
wrong!
4. First of all, this is not a GCR technology. As said it is more advanced and not static:
it calculates all colours indvidually. The result of that has a resemblance to GCR though.
But this technology has taken the print optimising as far as you can: which is not
possible with GCR. I think my examples describe that pretty well.
I have seen a poor copy of this software (it is very popular to make "save ink"
sofwares now) where they "save ink" (optimised, as I say) to a similar level as
in the software I use: they use GCR and the result was deviations in the colour: a blue
sky became grey. LOL!
The black start can be alterered in this software. I usually start around 5-8%.
Theoretically you could start at 1% but if the CTP has a problem to keep 1% to 1% it can
create problems: a small error in the high key can create a visual problem. So it is
better, according to my testing, to start aorund 5%.
5. "Partly gray and no gray component replacement!" Is this a question?
Please get back to me if you want more vaules or examples. I am not sure if it possible to
add attachments on this mailing list.
Cheers
A Sebastian
On Sunday, March 30, 2008, at 12:10PM, <eci-en-request(a)lists.callassoftware.com>
wrote:
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>Today's Topics:
>
> 1. Total Ink Coverage based on what? (Herr Spitfeure)
> 2. Re: Total Ink Coverage with GCR based on what? (Henk Gianotten)
> 3. Huang Xiang/CSU/UPM is out of office (Huang.Xiang(a)upm-kymmene.com)
>
>
>----------------------------------------------------------------------
>
>Message: 1
>Date: Sat, 29 Mar 2008 09:35:29 -0700
>From: Herr Spitfeure <achtung_spitfire(a)mac.com>
>Subject: [ECI-EN] Total Ink Coverage based on what?
>To: eci-en(a)lists.callassoftware.com
>Message-ID:
> <5B0763F2-0118-1000-A55B-9041CB0FFB42-Webmail-10008(a)mac.com>
>Content-Type: text/plain; charset=ISO-8859-1
>
>I am new here. Hi all of you!
>
>Here is my first contribution; a question regarding:
>
>
>Total Ink Coverage, TIC, for offset printing and the ink limits:
>
>
>In the past, when I worked in a analogue photographic enlarger, the TIC was not open
for discussions: we could not alter it.
>
>When we bought a drum-scanner and where able to handle the values (and not colours, by
the way) electronically we where now able to decide what TIC we wanted.
>The TIC's used where based on what people from Crosfield, Hell etc told us was
"good".
>For coated offset printing values around 375% where often used. Same for uncoated and
even for newsprint sometimes (at least in my company) until we learned more, usually from
other people in the biz, and then we lowered the values for uncoated qualities.
>
>Conclusion so far: TIC's where based on opinions and experience.
>
>Photoshop and other softwares where introduced and followed the pattern as with the
drum-scanners.
>
>ICC-technology appeared. Good ideas but not very high quality until maybe five years
back in history, generally speaking.
>Initially the ICC-technology created more "colour gurus" rather then good
quality.
>TIC's still based on opinions, "gray hair" and "experience".
>
>Some people in the biz started to alter values for TIC, often based on test-strips
with CMYK, from 400% and down: visual checks etc.
>
>Now:
>For several years we have had the technology to actually calculate the best possible
TIC in a scientifical manner but still many colour gurus use the "good old
default" values. For example: 300 to 350 for coated, 260 to 319 (ECI) for uncoated
and 220 to 240 for newsprint.
>
>Why do we not calculate the TIC's scientifically? Today we have the tools, I have
the tools and we use them.
>
>One example: for coated offset printed within ISO standards we base a neutral black on
around 340-350% and we reach L=10.
>>From that we allow the calculation to deviate delta 1 in L, not in a or b. A
engineer that I work with called this method JND, Just Noticeable Difference.
>This way we reach a TIC in neutral black that is 233% (two hundred and thirty three)!
In other words: we print neutral black with L=11 with 233%.
>Note: This technology do not set the TIC limit to 233 for all colours, it is
indvidual. A dark red can for example end up 244%. Normal ICC-profiles are in other words
a compromise: the TIC will limit all colours to one top value for TIC.
>One more example: for newsprint we have reached a TIC, for neutral black, around 180%
with a better L-value then ISOnewspaper26v4 - but a dark red can in the same print reach
209%.
>And so on.
>
>So, good bye to "opinions", "gray hair" and "experience"
or what is your opinion and experience regarding TIC?
>
>Best regards
>A Sebastian
>
>
>------------------------------
>
>Message: 2
>Date: Sun, 30 Mar 2008 00:43:50 +0100
>From: Henk Gianotten <henk(a)gianotten.com>
>Subject: Re: [ECI-EN] Total Ink Coverage with GCR based on what?
>To: <eci-en(a)lists.callassoftware.com>
>Message-ID: <5.2.0.9.0.20080330003025.00c1e220(a)pop.planet.nl>
>Content-Type: text/plain; charset="us-ascii"; format=flowed
>
>At 09:35 29-3-2008 -0700, A Sebastian wrote:
>
>>This way we reach a TIC in neutral black that is 233% (two hundred and
>>thirty three)! In other words: we print neutral black with L=11 with 233%.
>>Note: This technology do not set the TIC limit to 233 for all colours, it
>>is indvidual. A dark red can for example end up 244%. Normal ICC-profiles
>>are in other words a compromise: the TIC will limit all colours to one top
>>value for TIC.
>>One more example: for newsprint we have reached a TIC, for neutral black,
>>around 180% with a better L-value then ISOnewspaper26v4 - but a dark red
>>can in the same print reach 209%.
>>And so on.
>
>Nice figures but it's good to know how the CMYK combinations were created.
>Maximum K of 100%? "Dark Red" in newsprint 244% with still cyan in it
instead of K?
>Or in other words how long and
how wide are the GCR settings for these
profiles?
>Henk (Partly gray and no gray
component replacement!)
>
>
-----------------------------------------------------------------------------------
Henk Gianotten, Prins Hendriklaan 58 3761 DW Soest, Netherlands
Tel. +31 (0)35 60 12 206 Fax: +31 (0)84 73 04 497 e-mail: henk(a)gianotten.com
------------------------------------------------------------------------------------
>
>
>
>
>------------------------------
>
>Message: 3
>Date: Sun, 30 Mar 2008 07:48:18 +0800
>From: Huang.Xiang(a)upm-kymmene.com
>Subject: [ECI-EN] Huang Xiang/CSU/UPM is out of office
>To: eci-en(a)lists.callassoftware.com
>Message-ID:
> <OF83F2227C.F91F6783-ON4825741B.0082C408-4825741B.0082C408(a)upm-kymmene.com>
>
>Content-Type: text/plain; charset=US-ASCII
>
>
>I will be out of the office starting 2008-03-28 and will not return until
>2008-03-31.
>
>Pls Call me for urgent matter.
>
>
>
>------------------------------
>
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>End of ECI-EN Digest, Vol 25, Issue 23
>**************************************
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>