I have an iOS app written in Swift, where you can create images with texts etc. In the end, you can create a PDF, which is destined for printing. I've got a response from the printing house that it has to be in 300 DPI, which I've fixed, but they also require CMYK colour profile.

I've only found this post: Include ICC Colour Profile in PDF created with Objective-C iOS?

and the author states it's impossible. Also, this is stated in Apple documentation:

https://developer.apple.com/library/archive/technotes/tn2313/_index.html

These contexts let you specify a CGColorSpace:

CGBitmapContext CGWindowContext And these do not:

CGPDFContext CGPostScriptContext

But I cannot believe there isn't any other way. Even if it's not possible using pdfContext, there must be other API to do so. I've found other PDF-making libraries on github, but I haven't found any information in terms of colour profile support.