Fine Art Workflow Triage—Helping a Photographer Master Process Color

[jupiterboy]

I have an unusual challenge in that I am working with an arts institution and using their photography of art works in a typical Gracol workflow. The photographer comes from a background that does not include any concept of offset lithography. I am attempting to help with some very basic ideas, like white point adjustment. I have been successful in getting the images delivered with a Macbeth color checker in the shot. The first issue I note is that often, the white point square on the checker will arrive with 70–90% ink coverage. Because it is a fine arts workflow situation, no one ever touches or changes anything in the files. This means we get our first set of proofs back looking very dark, generally—too dark to even see color casts and other typical issues you might address in proofs. This becomes expensive, time consuming, and slow to correct by writing various corrective moves longhand on proofs. Obviously, it would be much better to have the original image,adjusted with the artwork in sight, delivered in a way that was more suitable to print.


All of this generally falls under the “my proofs are too dark” sort of discussion that is very common. My emerging issue is that the current publication features very dark, black-on-black paintings where we need to get the maximum distinction between subtle shades of black, which to my thinking is one of the most difficult print scenarios imaginable.


The photographer is very wed to the idea that (and his screen is calibrated and he does use wide-gamut monitors) his visual corrections on screen should be all that is required, and that someone else should fix the files. However, the primary moves need to be made while looking at the works, and the goal is to slowly move the workflow in a better direction.


I have found some workable color checker RGB values and reviewed basic ink density information with the photographer—setting white point and black point—and we are making some headway. Now after this long ramble, I am looking at some of his new images and noting how different the soft proofing looks between those adjusted by the numbers and those adjusted originally by eye by the photographer and then by numbers in a curves layer. While the RGB values for the checker are very similar, the mid tones in soft proof appear very different. The histogram is also slightly shifted and the process conversion numbers are different, even with similar RGB white and dark points.


My speculation is that the photographer has gone back to the original RAW files and has handled the exposure differently, which is resulting in less tonal compression and a shifted histogram, even while forcing the same white point and shadow.


Here are two histograms for the same image. Unfortunately, I can't show the actual images for legal reasons.



I have suggested that the photographer start using a light meter to check his strobes during capture. I would also like to find a way for him to use his very nice Epson printer and soft proofing to be able to anticipate and test his own correction. Right now, there is no way to calibrate the printer output and there is also no RIP so using the Epson for proofing seems very tricky—PDF X-4 being, to my thinking, maybe the best way to force the printer to use the Gracol gamut.

I sense the photographer's frustration, and am looking for suggestions about methods and ways to help him out, and in particular, ways to deal with very dark images and ways to help him accomplish more repeatable results in RAW.

All suggestions welcome.

 

[Tom Mann]

Putting in place a fully color managed workflow (GRACol or otherwise) is a non-trivial undertaking - not only the mechanics of it, but the psychology of it, as well (i.e., teaching and motivating everyone involved). So, let's start with some real basics:

1. No camera captures images in any of the GRACol color space variants. The camera will probably capture RAW data and that will eventually have to be converted (not assigned) to the GRACol space you want to use. Is this being done? If so, where in the workflow, and by whom? Where did you get the correct icc color profile?

2. Have you double and triple checked that the correct color space tag (icc profile) is present at every point in the entire workflow? For example, if your workflow is, say, RAW (from the camera) -> ProPhoto (for editing in the widest possible gamut) -> GRACol 7 XXX and then sent to the press tagged that way, and/or converted to a common RGB version (sRGB, Adobe RGB, etc.) to send to a local inkjet for soft proofing, then you need to check that the files are all tagged correctly at every point.

3. Have you put some well known standard color test images through the same workflow to make sure they come out looking good both from the offset press as well as soft proofs? You can't blame the photographer until you get standard color test images to work.

More later,

Tom M

 

[jupiterboy]

Putting in place a fully color managed workflow (GRACol or otherwise) is a non-trivial undertaking - not only the mechanics of it, but the psychology of it, as well (i.e., teaching and motivating everyone involved). So, let's start with some real basics:

1. No camera captures images in any of the GRACol color space variants. The camera will probably capture RAW data and that will eventually have to be converted (not assigned) to the GRACol space you want to use. Is this being done? If so, where in the workflow, and by whom? Where did you get the correct icc color profile?

2. Have you double and triple checked that the correct color space tag (icc profile) is present at every point in the entire workflow? For example, if your workflow is, say, RAW (from the camera) -> ProPhoto (for editing in the widest possible gamut) -> GRACol 7 XXX and then sent to the press tagged that way, and/or converted to a common RGB version (sRGB, Adobe RGB, etc.) to send to a local inkjet for soft proofing, then you need to check that the files are all tagged correctly at every point.

3. Have you put some well known standard color test images through the same workflow to make sure they come out looking good both from the offset press as well as soft proofs? You can't blame the photographer until you get standard color test images to work.

More later,

Tom M

Thanks for the comments, Tom. Images have come to me tagged with various RGB profiles. The current project has 28 Pro Photos in 16 bit and two Adobe RGB in 8 bit. I never change the native profile of an image, and they tend to come in from various sources with different tags, and occasionally, no tag at all. I simply size and transfer the files to the printer, as I am a vendor/book designer and the digital assets belong to the museum and are completely controlled by the museum. It would be poor practice for me to do anything. That said, I can offer advise once proofs come in, and they are proofs from the printer, typically sized scatters. The museum is always free to reject or accept any input from me in regards to the color work as they are producing the images for their own publications. The printer does all CMYK conversion based on the specific press the work will be printed on.

The photographer captures in RAW and then saves to whatever RGB space he chooses, which, by evidence, is inconsistent. I've encouraged him to consider carefully standardizing RGB color space based on what might give the best conversion. ProPhoto is beyond the gamut of a monitor, so I suggested he might try delivering in Adobe RGB, as it is within range of a better monitor, yet large enough to accommodate decent correction work. I would prefer to have all images in the same space and to be tagged. This is what I always request.

The photographer has an Epson printer, but it is not calibrated. There is no spectrophotometer on premises. I have walked through a workflow to force it to a generic Gracol profile. Still, it's not calibrated output. I've also been over ICC profiles and helped set up the various interactions in Photoshop to give decent soft proofing. I think this photographer is simply not accustomed to the compromises of CMYK, and is romanced by working on screen and delivering for web and apps.

As the title states, this is triage, and I'm introducing the idea of measuring greyscale values because we are going in with very dark images, which make the proofing expensive and time consuming. With this current publication, images are very dark, with all the ink in a very narrow, heavy band. I want to maximize the differentiation between the blacks. This particular artist has many books published on his work, and many feature images that are simply solid black. All detail is lost. I have an opportunity to show some works that have been very poorly reproduced in the past, but I can't expect this photographer to get fully up to speed and to master new gear in a matter of weeks. I'm also diagnosing the situation from the back seat, so to say, so I am having to guess about how the problems are being introduced.

Let me reinforce that I am not blaming the photographer, but I am trying to help the client control the budget and keep relations with the printer on a good footing. I have had complaints, and I understand the problem. All I can do is try and help get our first round of proofs to a better place. Removing 20% ink from every channel just to get the image to a place where it can be evaluated is a step that needs to be skipped.

 

[Tom Mann]

Hi Jupiter - Got your reply. Unfortunately, I can't respond right now, but will get back to you tmmrw.

Regards,

Tom M

 

[jupiterboy]

Hi Jupiter - Got your reply. Unfortunately, I can't respond right now, but will get back to you tmmrw.

Regards,

Tom M

Thanks, Tom. No hurry. This is an evolving issue. We've recently been able to get the photographer to lower his film speed down from 800, which was giving us an awful grain; to get rid of a set of mismatched lights that gave us green and pink casts in the same images; and to not crop out the color checker. He has new lights, and the captures are much better. We need to focus on the post work now, so any ideas I can use are most appreciated.