Understanding ICC Profile Conversion Messages During PDF Export in InDesign

Hi @lydiad95712137 , Does it happen if you Export to PDF/X-4? 

I get the message if I assign a v4 profile like Coated GRACoL 2013 to my document and Export to the PDF/X-1a preset. I think you can safely ignore the warning even with a PDF/X-1a export because the output CMYK conversion values are correct—if I do a Convert to Profile to Coated GRACoL 2013 in Photoshop, I get the same values relative to my color assignments and settings on an export conversion out of InDesign. I also get the same values when I compare InDesign’s Separation Preview values with AcrobatPro’s Output Preview Separation values.

I think there's better colour professionals on the forum than me but I'll give it a go. 

@rob day  I'm looking at you 😄 

So I think what is happening is that your document contains colour profiles that are based on the newer ICC (International Color Consortium) version 4 standard.

When exporting your InDesign file to PDF, the profiles were converted to ICC version 2, which is an older standard.

This is what might be happening.

Just because it's newer should it be used - I don't know if many have moved on from the ICC version 2 - so it might be more widely supported based on things like print service providers, older devices, and PDF viewers etc. ICC V4 may not be fully supported yet due to not being upgraded or advancing (why fix it if it's not broke, right!?) - it's worth asking your print provider if they support ICC v4 or not.

When InDesign exports it's converting the  version 4 profiles to version 2 which might be better compatibility with a broader range of devices and printers.

Again - just to keep saying it - If your workflow or print service requires specific colour accuracy, you might want to check with them whether ICC version 4 profiles can be used, or simply stick to version 2 profiles for easier compatibility.

Hope that helps explain some of it.