I found this thread, which is old and no longer open for new comments:
https://krita-artists.org/t/how-to-check-total-cmyk-ink-coverage-amount-in-krita/69838
That original poster had a very hard time getting his original point across, but eventually the need came through later in the discussion. However, the discussion doesn’t appear to have culminated in much progress in terms of new app features. It included a link to @EyeOdin’s ink_limit Github repo, but when I clicked the link, I learned that that repo no longer exists. EyeOdin has apparently deleted it since that discussion, for reasons unknown. At any rate, my understanding is that the plugin only addressed a minor issue of the overall problem: book-printers (e.g. IngramSpark) require that images not contain CMYK values above a total threshold (240%) (because the ink otherwise smears during printing). The plugin would have eased the need to visually sum up four values in the color selector. That’s helpful to be sure, but the plugin no longer exists, and it barely would have addressed the bigger problem anyway. Merely seeing eyedropper point-indications of over-limit errors in the color selector barely assists a user in actually fixing such problems. I believe the program needs the following three tools or features:
- The exact feature indicated in the plugin for which the repo no longer exists: the CMYK selector should show the percentage sum of the CMYK components, some value between 0% and 400%.
- There should be a out-of-“gamut”-like overlay on the soft-proof view that reveals not “gamut” errors but locations where the CMYK value exceeds some user-specified limit (e.g. 240%, IngramSpark’s currently documented restriction at the time of this writing). This feature would go beyond mere eyedropper point-selections to enable the user to get a global overview of which regions of the image are out-of-spec with regard to various book printers’ restrictions.
- Most importantly, there need to be tools to actually enable the user to fix the problem. The two previous items merely help the user find such problems. There should be a way to paint or fill or level-limit or truncate (choose your favorite term) any over-limit values to some limiting value, the sum of which does not exceed the limit in question. In most cases, this will probably be black, since that is the most common way to accidentally exceed a book printer’s restriction, so simply remapping all illegal values to 0%,0%,0%,100% might work – but that is an oversimplification. I can imagine someone producing a color book who is still subject to a total ink limit. In such cases, there needs to be a way to remap over-limit pixels (or regions) to some other within-limit value (it could be any conceivable color of course). I’m not exactly sure how to do that, perhaps just linearly pull all four components down until the sum is within the limit. That would probably impose color shifts, it’s a hard problem to solve, but something has to be done in these cases. Otherwise book publishers will reject the images and the documents that contain them.
Thoughts?
Hello