Issue rendering some gradients
If you change the the extension to .pdf, the gradient is no longer rendered. Rendering the .ai in other pdf interpreters also do not render the gradient.
More information: https://bugs.ghostscript.com/show_bug.cgi?id=704780#c2
See these examples.
file with 2 CMYK spots (as in original example file) and 1 CMYK process color renders as expected.
file with 2 CMYK spot colors (original example file) and 1 RGB "process" color does not render as you expect.
file with 2 RGB spot colors (original CMYK spots changed to RGB spots) and 1 RGB "process" color also does not render as expected.
Whether that's a bug or not I really can't say.
I would expect "general weirdness" when mixing RGB and spot colors though.
Ah, I see now
I suspect it has less to do with more than 2 stops and more to do with the mixing of spot and RGB colorspaces in the same gradient. A 3-spot gradient renders just fine in Acrobat w/o overprint preview.
Correct, that's what we've observed as well. Hopefully multiple color stops can be supported for a linear gradient.
In examining this file, I download the ai file and as usual it downloads as a PDF. I change the extension to *.ai and open in Illustrator.
I find that there is an extra RGB color in the gradient, at the "top".
See the screenshots "gradientExtraRGBstop" and "gradientExtraRGBstop-firstSpotStop".
If I take this file and save as a PDF and open in Acrobat, or open the PDF as downloaded in Acrobat, the green gradient object is rendered as white unless I turn on overprint preview, as noted.
If I remove the extra RGB stop from the gradient and then save the ai file with PDF compatibility and open in Acrobat (file is uploaded to the cloud, converted and downloaded again), the green gradient now renders correctly without overprint preview.
Also, If I remove the extra RGB stop from the gradient and then save the as a PDF and open in Acrobat, the green gradient now renders correctly without overprint preview.
Interesting. Turning Overprint on in Acrobat fixes displaying it white and render it green... on opening in Ai no traces of blend modes or overprint is seen.