ECI-EN March 2004

eci-en@lists.callassoftware.com

18 participants
16 discussions

AW: [ECI-EN] Solid densities and Tolerances

by Meinecke, Karl Michael (bvdm)

For clarification: There are no colour references included with the Handbook "ProzzessStandard Offsetdruck" (not generated during the recent printing of Altona Test Suite Reference prints and not from other sources). Density values are no longer used in ISO 12647-2 (2004). Freundliche Gruesse - Kind Regards Karl Michael Meinecke Bundesverband Druck und Medien e.V. (bvdm) German Printing and Media Industries Federation (bvdm) Biebricher Allee 79 | D-65187 Wiesbaden Postfach 18 69 | D-65008 Wiesbaden Fon +49(0)611 - 80 31 68 | Fax +49(0)611 - 80 32 68 mailto:km@bvdm-online.de | URL www.bvdm.org ------------------------------------------------------ NEU NEU NEU - Altona Test Suite Anwendungspaket www.altonatestsuite.de NEW NEW NEW - Altona Test Suite Application Kit www.altonatestsuite.com -----Ursprüngliche Nachricht----- Von: dolezalek [mailto:dolezalek@fogra.org] Gesendet: Dienstag, 2. März 2004 17:19 An: eci-en(a)lists.transmedia.de Betreff: AW: [ECI-EN] Solid densities and Tolerances there may be several reasons: 1) The colour references now included with the Handbook were generated during the printing of the altona test suite kit, they ought to conform to the revision of 12647-2:new and the accordingly revised table 7.4.1. The densities in 7.4.3 were put in against our strong advice. the were measured on old samples in 1995 which of course conformed only to ISO 12647-2:1996 at best (at that time there were no ISO 2846-1 inks available...cyan was probably on the reddish side). 2) the densities refer to paper white and status E with polarization filters and were measured with Gretag SPM 100 where one can switch polarization on and off. Those densities are not always the same as those of other Gretag densitometers. 3) the example goes to prove that density values are but a poor representation of colour, especially for C. We have distributed 15 000 copies of our "blue wonder" and MAN Roland has issuied another 10 000, where a (Standard) cyan colours pair was shown to have the same densities, but looked very different and another pair which looked much closer but had densities 0,3 apart. THIS HAS ALL BEEN IN VAIN! 4) The new ISO 12647-2 will show no more densities, it's no use. Regards Mit freundl. Grüßen Fred Dolezalek Dr. Friedr. Dolezalek FOGRA, Graphic Techn. FOGRA Forschungsges. Research Association Druck e.V. dolezalek at fogra.org Tel. +49-89-43182-311, Fax +49-89-43182-100 PO. Box 80 04 69, D-81604 Muenchen, Germany Streitfeldstr. 19, D-81673 Muenchen, Germany -----Ursprüngliche Nachricht----- Von: eci-en-admin(a)lists.transmedia.de [mailto:eci-en-admin@lists.transmedia.de]Im Auftrag von Jo Brunenberg Gesendet: 2. März 2004 14:49 An: eci-en(a)lists.transmedia.de; wowg(a)lists.callassoftware.com Cc: jos.hendriks(a)rotosmeets.com; jan.daems(a)rotosmeets.com Betreff: [ECI-EN] Solid densities and Tolerances Concerning: Solid densities and Tolerances In the BVDM publication "Prozess Standard Offset Druck " solid densities and tolerances are specified. The package also contains samples wit solid densities. ("Färbungsstandard") We have noticed a strange discrepancy between the specified CMY Lab densities and the measured CMY solid densities from the samples. We measured the Lab values and the densities of the papertype 3 samples. ("LWC Rollenoffset") - the Lab values are very close to the ones specified in Tabel 7.4.1 - the solid densities however differ quite a lot from the specified densities in table 7.4.3 density values in table 7.4.3 C 1,43 M 1,33 Y 1.26 measured density values of samples C 1,33 M 1,48 Y 1,24 Although we have noticed the description of table 7.4.3: "Unverbindliche Dichten der Volltonfärbungen.." we think it is strange that the density of Cyan is higher than Magenta in the table values whereas in the real measurements it is the reverse. Any ideas why this is the case? Best regards, Jo Brunenberg LOGIC USE BV (member of Roto Smeets De Boer) _______________________________________________ ECI-EN mailing list ECI-EN(a)lists.transmedia.de http://lists.transmedia.de/mailman/listinfo/eci-en _______________________________________________ ECI-EN mailing list ECI-EN(a)lists.transmedia.de http://lists.transmedia.de/mailman/listinfo/eci-en

20 years, 1 month

New ISO 12647-2 Spec.

by Alan Dresch

I do not normally contribute to mailing lists as I can't really justify the time. However I feel it is my responsibility to comment on the posting from Florian about using the "New" ISO Specification. My business is based on implementation of the ISO 12647-2 specification in Proofing and Printing applications. During the past couple of years I have developed a set of tools for critical colour print analysis and as you might expect I have become very familiar with practical implementation of the Specification. I have serious doubts about the measurement data from the 2002 print run which is the proposed target for the "New" spec. and I have fed back my comments to the ISO Committee. I am not sure where the Altona press run fits into the picture from the colour point of view, but I note from the literature included with the Altona prints that they are not intended for critical colour analysis, or words to that effect. 2002 Print run profiles and measurement data I have tested exhibits an unacceptable three quarter tone Blue (minus yellow) grey balance cast, and the solid colour densities are unrealistically 'vibrant' for practical implementation. Be careful with these profiles if you intend to use them for colour separation or if you intend them to be used as reference profiles in an ICC colour managed colour proofing application. Remember the "New" ISO 12647-2 specification is not yet published, it is in Draft Form only, and I would advise continued use of the 1996 specification until it is officially revised. Regards Alan Dresch Mellow Colour Mellow End Malinshill Road Evesham WR11 2QG Telephone 01386 421534 Mobile 07951 883608 Fax 01386 446590 email alandresch(a)mellowcolour.com web www.mellowcolour.com

20 years, 1 month

maybe a non-sense question ?

by Christian Kurek

Hello all, I'm just new subscriber to this list, and we are very interesting in colormanagement. We are pre-ress group, and we supply files for printers, offset and helio (roto) such as tiff/it p1, pdf, postscript or native document. We have proofers Cromalin Dupont AQ4, with curves in it to simulate LWC, euro15 standard, etc... So when we made proofer for helio(roto) we can after that made correction before printing to obtain good results. We manually compensate colours in Photoshop to reproduce as best in helio(roto) what is look like offset printing. But we do not compensate as well the pictures to the specifications of helio ! So I download from eci website (http://www.eci.org/eng/pages/profiles_e.html) the PSR Reference Colour Space LWC paper icc profile. I test this profile to automatically convert files with it in PageComposer RIP, in order to generate good separations for Heliogravure(rotogravure) . After that I made a print on Dupont Proofer with the PSR-LWC curve, and another with eurostandard15, to compare with the original (without conversion in PageComposer with ICC Profile) proofed with EuroStandard15. We see some difference beetween what we simulate in "Offset" and "Helio", and what we want is : - convert final page files for helio specifications - and compensate the default of helio to reproduce Offset colour as well. Because for example when we convert file (like IT8 file) with the PSR Reference Colour Space LWC paper icc profile, yellow benday 100% is convert like Cyan :4% Magenta: 3% Yellow 93% Black : 0% idem for Magenta 100%, Cyan 100%. Is it possible after convert files for helio specification (black generation, maximum ink etc...) to reproduce offset colours ? Our custommers print sometimes in helio, sometimes in Offset, and their logo company doesn't have the same look beetween helio and offset. And because our custommer validate the proofer with "Offset" simulation and finally he wants to print in Helio (because best price for example), when we made proof in Helio, all pictures looks differents, we must do corrections on files. After that, the files are specially made for Helio, and cannot be use for offset. Normally the ICC profile compensate the colour to reproduce as well the colour beetween two printer (for ex offset and helio). But it still have colour differences. How could you mase to adjust more efficiently colours ? By correction in Photoshop (made somes test and save "curve" to reproduce after that always the same corrections for all files?) ? Apply another ICC Profile ( I think no) ? I don't know so if you could have some ideas or same reflexions ? Another question : when I convert files with ICC profile, I do my proof without the PSR - LWC curve on Dupont Cromalin ( because it's like if a apply two times the helio simulation ), but with euro15 standard ? Best Regards Christian Kurek

20 years, 1 month

Solid densities and Tolerances

by Jo Brunenberg

Concerning: Solid densities and Tolerances Dear Mr. Dolezalek / Dear Mr. Meinecke, The measurements we were referring to were based on the "Färbungs "F

20 years, 2 months

Solid densities and Tolerances

by Jo Brunenberg

A part of the previous message was missing. So here it is once again: Concerning: Solid densities and Tolerances Dear Mr. Dolezalek / Dear Mr. Meinecke, The measurements we were referring to were based on the samples from the "Färbungs-Standard " published by BVDM in the year 2000. It was not clear to us that these samples were no longer valid. (Which might be the case for more owners of the "Färbungs-Standard") Now it is clear to us that in the new ISO standard densities are no longer specified. I realize that I have caused some confusion with my previous message. I am sorry for that. Best regards, Jo Brunenberg

20 years, 2 months

Solid densities and Tolerances

by Jo Brunenberg

Concerning: Solid densities and Tolerances In the BVDM publication "Prozess Standard Offset Druck " solid densities and tolerances are specified. The package also contains samples wit solid densities. ("Färbungsstandard") We have noticed a strange discrepancy between the specified CMY Lab densities and the measured CMY solid densities from the samples. We measured the Lab values and the densities of the papertype 3 samples. ("LWC Rollenoffset") - the Lab values are very close to the ones specified in Tabel 7.4.1 - the solid densities however differ quite a lot from the specified densities in table 7.4.3 density values in table 7.4.3 C 1,43 M 1,33 Y 1.26 measured density values of samples C 1,33 M 1,48 Y 1,24 Although we have noticed the description of table 7.4.3: "Unverbindliche Dichten der Volltonfärbungen.." we think it is strange that the density of Cyan is higher than Magenta in the table values whereas in the real measurements it is the reverse. Any ideas why this is the case? Best regards, Jo Brunenberg LOGIC USE BV (member of Roto Smeets De Boer)

20 years, 2 months

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ECI-EN March 2004