Illustrator file saved as PDF darkens picture color

Question

I have a CMYK document with a photo. I want to print it from a service bureau and saved it as PDF. The save dialog has no options for color management. The result in PDF has one photo with much darker colors compared to the original and to a PNG export:

The magenta background is also a bit darker, and the remaining colors seem OK.

The second time I saved as PDF, the background became black:

When I screenshoot the PDF file, the color in the picture becomes lighter inside the print screen selection.

I am running Illustrator CS5 and macOS Mojave 10.14.6.

Why does this happen?

Answer 1

It's difficult to say what's wrong. It could be one of many things. Here are some things to consider:

1. Some consumer grade digital photo printing services (and desktop home/office inkjet printers) expect RGB image files, with an sRGB colour profile. They aren't set up for printing CMYK images at all. Professional grade digital printers should be able to handle them though. I don't know anything about your print provider - perhaps it would be better to ask them the question.

2. PNG is not a print format. It only supports RGB and Indexed colour. Don't use PNGs for print. They are designed for on screen use. Consider using another format instead, such as PSD, TIFF or a high quality JPEG instead.

3. On the other hand, normally, a PDF should print just fine digitally, whether it's CMYK or RGB, whether printed professionally or not. Adobe Reader can be used to print CMYK images even on a home inkjet printer. However, there's no guarantee your print provider is using Adboe Reader to print the file. There are many PDF viewers, and not all of them are good.

4. If you have a CMYK document, but with an RGB image inside it, then that might explain the problem. Again this is just a hunch, not a fact. You might want to consider using a CMYK raster image such as a PSD/TIFF, and use a suitable colour profile. Your printer may be able to help you with this if you ask them.

5. Alternatively, you might just be better to provide an RGB document with an RGB image embedded.

Obviously, I don't know which of these approaches will work best for you. Your print provider may be able to offer you better advice since only they know their own capabilities.