December 2003 - ECI-EN - lists.callassoftware.com

by Bestmann, Guenter 3887 S-PN-RD11

Hello, to my understanding there are no reasons for different grey balances in AdobeRGB, eciRGB and sRGB. The only differences between these RGB definitions are the gamma curves or tone response curves. Equal R=G=B will result in slightly different L* values with a*=b*=0. The difference between AdobeRGB and sRGB on the one side and eciRGB on the other side are the color temperatures. The first ones are defined with respect to D65, eciRGB is defined for D50. During transformation to or from eciRGB no color appearance matching due to the different color temperatures of RGB and CMYK (these profiles are always defined for D50) is necessary. But the effect of the color appearance matching will not result in worse grey balances. Kind regards, Dr. Guenter Bestmann Heidelberger Druckmaschinen AG Solution Center Sheetfed S-RD-PN7 Dr.-Hell-Straße D-24107 Kiel, Germany Tel.: +49 (0) 431/3863887 Mail: Guenter.Bestmann(a)Heidelberg.com <mailto:Guenter.Bestmann@Heidelberg.com> -----Ursprüngliche Nachricht----- Von: eci-en-admin(a)lists.transmedia.de [mailto:eci-en-admin@lists.transmedia.de]Im Auftrag von Jo Brunenberg Gesendet: Montag, 8. Dezember 2003 11:19 An: eci-en(a)lists.transmedia.de Betreff: [ECI-EN] ECI-RGB / Any advantages? CONCERNING: ECI-RGB / Any advantages? At a recent meeting I heard that the application of the ECI RGB ICC profile would result in a better grey balance. I made a number of tests on this subject but did not find any proof for this statement. See test description and results below. Could anyone explain to me in which workflow it could be advantageous to use the ECI RGB ICC profile? Thanks for any comments! Best regards, Jo Brunenberg Senior technology consultant Prepress / ICT LOGIC USE BV member of Roto Smeets -------------------------------------------------- Test description - Test image: TC 2.88 (RGB target with colors covering complete RGB colorspace, including neutral greys, saturated and pastel colors etc. - I made the following versions of this file: 1. assigned sRGB 2. assigned Adobe RGB 3. assigned ECI RGB 4.assigned a scanner-RGB 5. converted to profile: sRGB 6. converted to profile Adobe RGB 7. converted to profile ECI RGB Next step: All 7 RGB-files were A) converted to profile (CMYK) with profile ECIwebcoatedsb.icc B) converted to profile (CMYK) with our custom web offset profile Next step: All files were proofed on IRIS A) with profile ECIwebcoatedsb.icc B) with our custom web offset profile Results: - No differences in grey balance between A and B - No differences in grey balance between all 7 versions on proof A and B - Only the following differences between A and B: - Some more color saturation in proof A - Some more shadow detail in proof A These last two observations can be explained by the fact that the ISO profile (printed on a sheet-fed press) has a larger color space compared to our custom profile. (printed on a web press). _______________________________________________ ECI-EN mailing list ECI-EN(a)lists.transmedia.de http://lists.transmedia.de/mailman/listinfo/eci-en

20 years, 4 months

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Tom Galt/Mt Morris/QW1/US is out of the office.

by Tom.Galt＠quebecorworld.com

I will be out of the office starting 12/12/2003 and will not return until 12/16/2003. I will respond to your message when I return.

20 years, 4 months

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ISO 3664 and ISO 12646

by Per Savander

Could somebody please shine some light on the application of the standards regarding light conditions in the field of prepress, press and photography. The two standards ISO3664 and ISO 12346 are appearantly the main source of information. I will be writing an article to a magazine about the light and environment in color critical workflows, and would like to have the facts right (who would not;-) Light quality is ths same in ISO 3664 and ISO 12646 -D50 -CRI>90 -Metamerism index<4 Is the RA-index (should be over 90) the same as the tube-manufacturer´s class A of tubes? Would not halogen-lamps be better than tubes due to the more even spectrum, tough I have not found a true D50 halogen (closest Solux is 4700K) Ambient surroundings are the same in ISO 3664 and ISO 12646 -Color evaluation on monitor ambient light 32 rather than 64 lux -Indirect lighting -neutral matte munsell 8 surroundings -monitor hoods to avoid glare Proof evaluation are the same in ISO 3664 and ISO 12646 1500-2500 lux (which is prefferable?) Monitor whitepoint is not the same in ISO 3664 and ISO 12646 ISO 3665 monitor whitepoint D65, 75-100 cd/m2 ISO 12646 monitor whitepoint D50, 80-120 cd/m2 -what should be used, D65 or D50 (we know the problem with D50-too yellow, D65 sometimes too cold) -we have made some tests with LCD:s and noticed that D50 can give a better match than D65 (to a D50 output profiled proof matched in D50). -people often ask me why software vendors recommend D65 monitor whitepoint tough proofing boxes are D50. Warum? -many non-icc color matchers use D65 for industry color matching and even ink-mixing. - why? -any standard-based recommendations on black level luminance on monitors? -when will the 12346 be final? Well, there was many questions for all you out there, and I wish that you cold give some fact-based answers. Especially the calibration and profiling of monitors is a field where there is a lot of questions around about the whitepoint and luminances. When we add the difficulty to match LCD:s (with ICC-profiles, not editing them) of different vendors with eacother, the unawareness seems to be quite extensive even among the pros. Thank you & kindest regards, p e r -- Per Savander, PrePress Center Oy, Turunlinnantie 8, 00930 Helsinki FINLAND tel: +358 (0)9-34364020 GSM: +358 (0)50-5639200 fax: +358 (0)9-3445455 http://www.prepress-center.fi -Dealer of computer, software and peripheral solutions for graphic arts and visual digital communications http://www.prepress-center.fi/icc -Solutions for icc color-management and workflow color control http://www.prepress-studio.fi -Training and consulting for graphic arts and visual digital communications

20 years, 4 months

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"broken" profile

by Jo Brunenberg

Hello list members, See attached image. This is a view of an ICC profile at different lightness levels. It shows at certainly lightness levels a discontinuity. The profile was made with ProfileMaker 4.1 from an ECI 2002 Random target printed in weboffset. Does anyone know what might be the cause? Best regards, Jo Brunenberg

20 years, 4 months

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RGB working spaces with printing gamut

by Jan-Peter Homann

Hi list In the past we had several discussions about the optimal gamut of matrix based RGB-profiles as workings space for Photoshop ans other imaging applications. Matrix based working spaces are representing a virtual monitor with additive color mixing. The print process is made by subtractive color mixing. So the gamut of matrix based RGB-Workingspace is always very different to any printing working space. At the moment I know about two projects which are working on a RGB-working space, which has gamut according to a wide gamut printing process and an ideal RGB greybalance. One is the project http://www.photogamut.org which is now only available in german language, but at the end of next week also in english And the second project is the "reference medium gamut" of the ICC The ICC project "reference medium gamut" as I understand it now, will change a lot, how gamut mapping will be done in the future with ICC-profiles. Today, the calculation of the gamut-mapping for the perceptual intent is a secret of every vendor of ICC-profiling software. Mapping High-Gamut RGB-Images to a printing space with perceptual mapping results to differnt results in the saturated colors and to different tonal adjustments. The concept of a "reference medium gamut" gives two advanteges: First, only very saturated colors, which are even not printable with wide gamut printing processes will get some slight gamut mapping. If all color corrections and image optimizations are done in this colorspace, a relative colorimetric match (may with blackpoint compensation) to the target printing space will lead to very good results. The problem of blue turns purple or red turns to orange is minimized. For printing processes with a very small gamut, the "reference medium gamut" is a reference for calculating the perceptual mapping. As the normal perceptual mapping is calculated also for very big source gamuts, this new approach should result to a perceptual mapping, which is not compressing too much normal saturated pictures. In the next step, not only pictures but also spot colors are represented inside the reference medium gamut. So pictures and spot colors can be alway mapped with the same gamut mapping strategy, which makes wokflows for the complete document much more simple. At least, the reference medium gamut makes it possible to go big steps forward in the field of quality control for color management workflows. With a set of reference pictures and technical elements, it is possible to make visual inspections, if the gamutmapping from the reference medium gamut to the most used printing spaces (eg. SWOP, GRACoL, ISOcoated, Newspaper etc...) gives the results we are expecting. In germany, there is next week a meeting about standards and qality control for digital photography at the DIN (German Institute for Standards). One project is so called "Masterproof for RGB-Data" which allows photographers to deliver data in a standardized RGB-Workingspace with printing gamut and a printed proof of this data including a digital control strip for control-measuring the proof with a spectrophotometer like the EyeOne. A first prototype of the control strip and the possibility to use the free gretag macbeth measuringtool for the RGB-proof verification should be available in january. -- Looking forward to quality control for color management workflows :-) Jan-Peter -- colormanagement.de ---------- fon/fax +49 30 611 075 18 Jan-Peter Homann ------------- mobile +49 171 54 70 358 Kastanienallee 71 ------- http://www.colormanagement.de 10435 Berlin --------- mailto:homann@colormanagement.de

20 years, 4 months

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Jörg Sulies/Minolta_Europe is out of the office.

by Joerg_Sulies＠minoltaeurope.com

I will be out of the office starting 08.12.2003 and will not return until 12.12.2003. Please contact Mr. André Ziemann in this time (Tel. +49(0)511/7404-393, e-mail andre_ziemann(a)minoltaeurope.com) will respond to your message when I return.

20 years, 4 months

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Tom Galt/Mt Morris/QW1/US is out of the office.

by Tom.Galt＠quebecorworld.com

I will be out of the office starting 11/29/2003 and will not return until 12/08/2003. I will respond to your message when I return.

20 years, 5 months

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ECI-EN December 2003