Thanks for sharing the info. I do occasional flat art reproduction work for artist friends but not nearly enough to justify a dedicated stand or C1-CH. My process is very similar to what you outline using bespoke profiles, XF3100, flash and LCC, but I have been using a standard ColorChecker and ProPhoto RGB values. My goal is slightly different too. Rather than a technical match I frequently have to make adjustments so that reproduction prints match the colors of the original and some painters are VERY sensitive to color.
Indeed, once you add monitor viewing, printing and a subjective client into the equation the number of variables greatly increases.
One thing to consider (not addressed in the guide) is the relationship between your capture illumination and your proofing illumination. When using strobe for capture illumination it is not possible to use the same illumination for proofing.
A lot of repro folks still use old GTI proofing booths, many of which are old CFL technology and which have surprisingly poor spectrums for something billed as a "proofing booth" or worse just use whatever room lighting they have or stand by a window. Many of our clients now use
DT Photon illumination for both capture and proofing; not only is the light extremely high in CRI/CQS using the same light for both purposes eliminates one (very important) variable from the color matching/reproduction/approval process.
In any case I'd argue (pretty strongly) that getting a highly consistent starting point is still of great value, even when subjective ("client is always right") changes are required downstream. With a consistent starting point such changes can often be made by Color Editor modification which can then be rolled into a preset or style and reapplied when similar situations arise in the future (e.g. to satisfy a particular artist you need to shift red toward yellow by 2.3 points). It's not always this simple or consistent, but every bit helps.
Parts of the above are discussed in our
lighting webinar.
I do have a question though; why do you specify Adobe RGB 1998 rather than ProPhoto RGB? It's not unusual for oil and acrylic paintings to have colors that are out of gamut for my Epson 9900 so they would probably also be out of gamut for Adobe RGB 1998. It seems that by starting with the smaller color space you run the risk of compressing colors early in the process and loosing the option to make informed decisions later.
I agree entirely. Research on this topic done by Dr. Roy Berns (RIT) confirm that artist paints often exceed smaller color spaces. The use in this document of Adobe 1998 in the various examples is specific to it's prevalence in the specific community we serve. Partly that prevalence is due to the 2010 version of the FADGI Guidelines (page 46) which specifically recommended Adobe 1998; the recently released 2016 FADGI guidelines are more accepting of either Adobe 1998, ECIRGBv2, and Prophoto profiles). I did not include any discussion of this in the guide, but your comment/question makes me think maybe we should include a paragraph or two about this (it is an intro document, but a light discussion might still fit).
If you want to really go down the rabbit hole we sell an Image Science Associates Artist Paint Target which is basically a target with the patches missing, and magnetic blank patches which you can paint (with actual paint relevant to a specific artist). We (or you if you have the skills and gear) can then measure those patches and create a Capture One overlay that has the nominal values for those patches in your desired color space. This custom target can then be included instead of or in addition to a Color Checker or ISA target, and you can use programs like SpectraShop to simulate the effect of different color spaces on that color and anticipate metameric failure under different illuminants. None of this is really something I'd recommend for someone who only does repro occasionally as there are obviously diminishing returns with this far greater effort.
