Notes on Color

The main modifications of ISO 12647-2:2013+

Fogra Extra 30 - The main modifications of ISO 12647-2

By reflecting the prevailing printing stock ISO 12647-2 now defines new printing substrates. This was necessary since PT3 and PT5 of the “old” ISO 12647 were barely available on the market anymore. The same can be found for coated stock that comprises a higher amount of OBA (Optical Brightening Agents). The discussion within the committee (TC130 WG3), significantly supported by the paper industry (Paperdam Group), showed that 8 new printing substrates are required to reflect the most important “clusters”.

iOS and its Apps are Not Even Color Managed

via petapixel

The M Factor...What Does It Mean?

New White Paper from X-Rite.

As part of ISO 13655-2009, a new measurements standards “M” series of measurement illumination conditions has been defined by the International Organization Standards [ISO] to standardize illumination conditions appropriate for different applications when substrates contain brightening agents. The new M series allows color management of OBA-enhanced substrates to be further refined to a very high degree.

New print characterizations FOGRA 48/49/50

Berlin/Munich/Wiesbaden, February 15, 2012: In the light of the established collaboration between the European Color Initiative (ECI), Fogra and the German Printing and Media Industries Federation (bvdm), the Fogra characterization database has been extended to three newly developed sets of characterization data.

While FOGRA48 addresses heat set printing on improved newsprint stock FOGRA49 and FOGRA50 cover standardized offset printing based on FOGRA39 with additional surface finishing namely matt and glossy laminated sheet-fed offset prints using OPP films.

Fogra and ECI released new profiles for web offset

Fogra together with ECI released new characterization data and profiles for web offset printing.

For four new printing conditions, published by Fogra in July 2008, ECI offset profiles are available as extension to the package “ECI_Offset_2007”.

The two profiles for heatset web offset printing on MFC paper (machine finished coating) and SNP paper (standard newsprint) are based on an extensive test print series conducted by the ECI Working Group Web Offset printing with substantial contribution from the bvdm.

ICC released new sRGB profiles

ICC released new sRGB profile (sRGB_v4_ICC_preference.icc) to better support version 4 ICC profiles. Additionaly two sRBG profiles version 2 were released (sRGB_IEC61966-2-1_noBPC.icc and sRGB_IEC61966-2-1_withBPC.icc) with better forward and backward compatibility in mixed workflows

Summary: Overall users can expect to get better and more consistent results using the sRGB v4 profile versus the sRGB v2 profiles. More details are available in White Paper 26.

Fogra39 substitutes Fogra27

It is official - Fogra39 is here to replace Fogra27. Long rumored Fogra39 dataset is published by Fogra. Additional details about Fogra39 dataset can be found here. Thanks Kamil Tresnak for info about this.

Due to this changes a new characterization data set has been created namely FOGRA39. It totally reflects the current primaries defined in ISO 12647-2 DAM 1. Problems and difficulties due to different aim values between the proof and the one stipulated in ISO 12647-2 belong to the past. However it was necessary to slightly adjust the secondaries green and blue toward more practical aim values.

Universal characterization data

Another meeting and again discussion about mysterious fogra39 dataset and amendment for ISO 12647-2

Dr. Dolezalek reminded the committee that he had proposed a sizeable number revisions to 12647-2 in San Diego that had not been discussed then. As a follow up, he proposed that the committee immediately write an amendment to the standard that changed the TVI curves to now reflect the shape produced by a 1:1 mapping (often referred as “natural behaviour”) at the platemaking stage, reported by Hutcheson and Kraushaar. He believed that one single curve with tolerances could meet all the committee requirements and be rapidly implementable. Based on that curve characterization data sets could then be developed for the individual paper types. After some discussion on the number of curves required, the committee accepted the proposal.

Printing Inks - Europe versus US

There is little difference in Printing Inks for Europe, US and Japan...

ISO 2846-1 deals with both the color and the transparency of the ink set. When we started working on it, we thought that we would have three sets of target numbers: one for the United States, one for Japan and one for Europe. That was because we thought the European standard for cyan was much redder than either SWOP or the Japanese standard (see first graph).

About two years into the process, though, when we actually started measuring proofs and comparing numbers, we found that the colors were all very close. So we were able to select a point for the new ISO standard that was an average of those three and specify a tolerance that would allow them all to meet the new standard.

Paper types and ISO 12647-2

Paper influence on color is sometimes forgotten. Other presentations from Paper Clasification Meeting in Leeds can be found here .

Fred Dolezalek stated that ISO 12647 was largely based on European input. Now we are in a better position to update the standard. He also observed that the shades specified in ISO 12647 were intended for proofing, but people expected to also use them in process control for production (where different tolerances apply). The market had developed since the ISO 12647 specification was published and it was certain that the paper types on the market will be different in another ten years. Another participant noted that classification properties need to be based on what is actually used in the market – for example, European papers are bluer than ISO 12647 shades..

What is "neutral"?

Interesting to read, for those interested how ISO standard 12647 for offset printing evolves. It looks like, we have to oposite camps - Europe and America. But what we are really missing is exact definition what is neutral.

The example also showed that a shift in the primary specification from "tone value aims" to "grey balance aims" does not only require an agreement of a suitable grey condition (process-specific or universal?) but a workable definition of what is neutral.

Note added in retrospect: The exact definition of what is "neutral" was not settled in the meeting.

Yes, these color photos are more than 100 years old...

Did you ever heard, about one of inventors of color photography, Russian photographer Prokudin-Gorskii?

We know that Prokudin-Gorskii intended his photographic images to be viewed in color because he developed an ingenious photographic technique in order for these images to be captured in black and white on glass plate negatives, using red, green and blue filters. He then presented these images in color in slide lectures using a light-projection system involving the same three filters.

Color Management is not that easy ...

This is my favorite quote of ICC specs, it is not that easy, as it can seems..

The mechanism can be modeled as follows: Through some means, the system infers the color and strength of the presumed illumination source. (In a normal scene, this inference may be based on specular highlights, or the apparent colors of known objects, or some kind of scene average, etc.; for reproductions, the inference may be made from the image itself or, as when viewing reflection prints, objects in the real world surrounding the image.) The system then uses this information to adjust the "gain" applied to the "cone responses" to the color stimuli (the actual process is not well understood, and is most likely more complicated)..
Page 101 (Chromatic Adaptation)

How aperture in your camera lens influence resolution

Today's high quality color films do reach resolutions in the region of 140 line pairs per millimeter with Kodak Ektar 25 leading the field at 200! The full resolution potential of these films cannot be utilized with existing depth-of-field concepts nor f-settings of f/11 and beyond.

Lowest Delta E "problem" recognized by ECI

Finally Lowest Delta E "problem" is recognized and acknowledged by ECI guys :-)

A proof which is a near-perfect match (∆E < 1) by measurements is usually not visually perfect! (Page 20)

ICC on UV filter and backing

Contrary to ISO and Fogra, ICC org recommends to use UV filter.

ICC bases this recommendation on two factors. First, the UV excitation in measurement is likely to be different from one instrument to another, as well as varying from that in the source of illumination used for viewing the print. For this reason the measured stimulus can only be an approximation that may, or may not, produce a color measurement closer to the perceived print color. Given this uncertainty, greater consistency between measurements is likely to be achieved if the UV is excluded

Euroscale is dead - long life to ISO 2846-1

No longer available from FOGRA site, hopefully they don't mind when it is republished here.

The „European Colour Scale“ is dead! Since a long time, process colours have shifted away from the original specifications laid down 1975 in the old International Standard ISO 2846...

Reference printing conditions: Where Can it Lead Us?

Interesting article about color gamut of offset printing

Substrate-referenced colorimetry seems to minimize differences in apparent gamut between printing on papers of different reflectance (brightness). However, a lot more work appears to be needed to understand the mechanisms involved and their impact on the process of establishing density aims for process control. Further, these types of data need to be analyzed using three-dimensional models rather than multiple two-dimensional projections.