CMYK to RGB graphics lose quality

[Irene Martin]

I am needing to export an interactive PDF. Currently, the transparency blend space is CMYK, but when I try to export, I get a warning that the file needs to be RGB for an interactive PDF. When I change the file to RGB, the links are pixelated and low quality in the exported PDF. The links in the file are all RGB .psd or .ai files. I have done this type of document many times before and have never had this issue.

Thanks,

Irene Martin

[Frans v.d. Geest]

Fitst try to export and ignore the warning (it is about transaparency) and look at how it looks. Does all look fine? Than ignore the warning.

Did you change the Document Blend Space to RGB? Then you should see no warning. Is this what you have done and after that the images looks pixelated?

[Irene Martin]

Yes, I have tried forcing the export anyway, and I've also tried to change to RGB before I export with the same results both times.

[Frans v.d. Geest · Accepted solution]

Then it is some resolution problem: I've seen this on iPDF sometimes. If the links are all linked then try upping the resolution in the export options when exporting to iPDF. Or, if there are no buttons, animations etc try exporting to a 'normal' PDF  and tick on hyperlinks etc. in the export options.

[Irene Martin]

I had set the JPEG quality to maximum, but the ppi was too low. When I set that higher, it fixed the problem. Although I still got the warning about needing to change to RGB.

Thanks a lot!

[rob day]

Although I still got the warning about needing to change to RGB

Hi Irene, The CMYK Blend Space warnings can be confusing. You don’t have to change the blend space to RGB, the warning is just letting you know there might be a color appearance shift when CMYK blended objects are converted to RGB on the export.

With Interactive PDFs all color gets converted to sRGB, and live transparency effects are blended as RGB, so only certain Blend Mode Effects would change appearance on export.

Here I have a yellow fill set to the Screen Blend Mode with the Document Transparency Blend Space set to CMYK. In this case all of the color exports to an Interactive PDF with the same appearance except for the Screen effect, which blends differently when the blend space is set to RGB:

In general you won’t see any color changes unless you are using Blend Modes that are affected by the CMYK vs. RGB Transparency Blend space:

[Frans v.d. Geest]

Which version of InDesign?

What OS?

[Irene Martin]

InDesign 17.2 on Windows 10 Pro