Transparency blending color space: sRGB IEC61966-2.1 in generated PDF

[piovasco]

Hi guys. For test purposes, I set up a extremely simple CMYK Publisher document (Fogra 39 profile). I simply drew a vector object (a "donut") and rasterized it within the document. I then exported the pdf with the option "ready to print". Adobe Acrobat DC's output preview correctly detects transparency, and shows a "Transparency blending color space: sRGB IEC61966-2.1" despite of the CMYK color space. Is this normal?
Thank you in advance for your time.

Attached are the files I used for the test.

files.zip

[lacerto]

Obsolete.

[Lee D]

@piovasco Thanks for your report, this is an existing issue that's logged with the developers I've added your report to.

[piovasco]

Thank you Iacerto for your superb explanation

[piovasco]

@lacerto Beyond the bad artifact you may see in print, a serious problem is that preflight software may reject PDF file because of the RGB space used for transparency blending. I love Affinity products, but if they want to be truly competitive even on the professional printing side, they need to fix these issues as soon as possible. If these issues are not resolved, people will find themselves forced to continue using competing software because they provide more reliability in PDF generation. And that's a shame, because Affinity would be truly outstanding.

[lacerto]

Obsolete.