Dear Jan-Peter, Dear PAB members,
I would like to bring to your attention the following news regarding ISO printing standards:
- ISO 12647-2 - 2010 revision (currently in draft stage):
Paper categorization has been completely revised in the new edition of the standard.
Eight paper types have been recognized to better reflect papers that are used by the industry and produced by paper manufacturers.
ECI/FOGRA and IDEAlliance characterization data will probably have to be updated accordingly.
We are hoping that, with the revision of ISO 12647-2, and the development of the new ISO 15339 standard (Printing from digital data across multiple technologies), there will be an opportunity to bring all existing characterization data together and offer one data set for each paper type to be used globally in standardized workflows, virtually regardless of the press technology (analog or digital) and calibration method (TVI or Near-Neutral reproduction).
- White and Black Backing characterization data:
Currently ISO 12647-2 normative aim values have been defined with black backing, mentioned white backing values are intended to be informative.
However, most if not all currently available characterization data is obtained from white backing.
We are currently working on recognizing D. Q. McDowell's White/Black Backing conversion method in the new revision of ISO 12647-2 - 2010 revision (currently in works) for measurement backing correction, but also for paper correction.
This would offer the practical advantage of enabling the correction of:
- measurement data when actual backing is different from ISO Standard or Characterization Data backing
- solid colors aims when actual paper color is different from ISO Standard or Characterization Data paper color for the same paper type.
When this step forward will be accomplished, provided the international community supports it (including you via your national body), most of the problems JP is mentioning will be practically solved.
Completely solved? probably not... Solved to a satisfactory degree? probably yes.
Kind Regards,
Elie Khoury
------------
On May 31, 2011, at 22:32 , Jan-Peter Homann wrote:
Hello all together,
I´m currently discussing with a paper manufacturer recommendations for
FOGRA char-data / ECI-profiles for his papers.
For woodfree uncoated papers, it seems clear, that FOGRA 47 /
PSO_uncoated_eci.icc should be used.
But digging a little bit deeper into paper categorization and printing
standards, the situation is not so clear.
If we look at the gamut, FOGRA47 /PSO_uncoated is smaller than e.g.
FOGRA40 / sc-paper.
If we are looking at the the traditional paper categorization for
heatset printing, the WFU (Wood free uncoated) papers are representing a
higher quality grade than SC papers (both are uncoated materials, but
SC-papers have a higher amount of wood fibers than wood free papers...)
So far as I learned about traditional paper categorization, the WFU
papers can may be super calandered or not. If not, this are the typical
uncoated papers, which are used e.g. in sheetfeed offset printing with
data preparation according FOGRA47 / PSO_uncoated.
If they are super calandered (WFU SC), they are more comparable with the
SC-paper category but with a much brighter paperwhite.
*****************
L*a*b* 100 K an 100C 100M 100Y for FOGRA 47 and FOGRA40
*****************
Source: MedienStandard Druck 2010 from bvdm
FOGRA 47 Black Backing
100 K = L*31 a*1 b*1
100C 100M 100Y = L*32 a*0 b*0
FOGRA 47 White Backing
100 K = L*31 a*1 b*1
100C 100M 100Y = L*33 a*0 b*0
FOGRA 40 Black Backing
100 K = L*22.2 a*0,9 b*2,1
100C 100M 100Y = L*26,2 a*-1,6 b*-3
FOGRA 40 White Backing
100 K = L*22.4 a*1,1 b*2,3
100C 100M 100Y = L*26,6 a*-1,5 b*-2,8
The comparison of this values, shows, that the densities / amount of
color for FOGRA 47 (uncoated) is much lower than for FOGRA40 (SC-paper).
Especially for WFU SC, this leads to following question:
- If ISO 12647-2 papertype 4 is used as standardization target and FOGRA
47 / PSO_uncoated for data preparation, we have a quite small gamut
compared to FOGRA 40 / SCpaper.
On the other hand FOGRA 40 / SCpaper could not used as target, because
the whitepoint of WFU SC is very different to FOGRA 40 / SCpaper. A
better candidate for gamut and paperwhite could be theoretically FOGRA41
/ PSO_MFC. But technically , this profile represents another paper category.
Another possibility would be, that the paper manufacturer adapts the
available standardization targets, publishes target values for white and
black backing and makes characterization-data and an ICC-profile public
available. For PDF/X workflows the characterization-data would be
registered at http://www.color.org
I would be interested to hear what other people are thinking about this
issue
Best regards
Jan-Peter
--
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homann colormanagement --------- fon +49 30 611 075 18
Jan-Peter Homann ------------ mobile +49 171 54 70 358
Cotheniusstr. 3 -------- http://www.colormanagement.de
10407 Berlin -------- mailto:homann@colormanagement.de
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