I'm close to finishing a proofable version of a photo book of black-and-white images and plan to publish it as a paperback on KDP.
In the KDP forums, another photographer/author has found that for some images, submitting the PDF with RGB images works better than in CMYK. He suggested I do a test book with duplicate files, one set in RGB and the other in CMYK, and output to PDF/X-3. The images are now in Photoshops Grayscale mode, using the Gray Gamma 2.2 profile.
I'd like to test this. It occurred to me that instead of producing a sample book with image files in two (or is it three?) color spaces, I could print three books, one with the Gray Gamma files, one with images converted to RGB, and a third with images converted to CMYK, and that I could do the conversion to the different color spaces in InDesign rather than creating a new set of files in Photoshop.
Is this possible? It seems, when I experimented, that I could get RGB output by specifying the RGB transparency blend mode and then converting to and specifying sRGB as the output space. But I haven't been able to figure out how to convert to CMYK.
When I convert a few test images to CMYK in Photoshop and then output a test file to PDF/X-1a or PDF/X-3, the CMYK images look right in the Acrobat Reader, but the unconverted images that are still in the Gray Gamma space look washed out, which tells me they are not probably not converted. Also, the PDF output file is only increased by additional size of the test CMYK images.
What am I doing wrong? Or is it not possible to get InDesign to do a bulk conversion of the images to CMYK?
I agree, but it is curious that the KDP recommendation is to provide flattened CMYK with no profiles (PDF/X-1a with no output intent!).
It is, for whatever reasons, probably what works best for them—in that, taking in mostly amateur/novice files, it give a more consistent result than the whopping spread that RGB might bring.
As for 'recommendation,' if you've spent any time reading or trying to keep up with KDP's rules, regs and standards, you know that they're about one-third verities, one-third out of date and one-third too vague or novice-speak to be useful.
Don't get me wrong: I think KDP, all financial and corporate-political issues aside, is a huge boon for small and even not so small publishers. But while print quality is good and trending better, color management is never going to be better than the local FedEx Office or Kinko's.
|| Word & InDesign to Kindle (& EPUB): a Professional Guide (Amazon)