How to change the CMYK values for entire document?

[Nooner911]

I have a label printer that prints very dark (I'm guessing the RIP sucks?) and requires a PDF file. So I use Illustrator to create the PDF print file with registration marks for cutting, etc. I've identified that it adds about 20% too much black to darker colors. Is there any way to decrease the black (or any of the CMYK values) of everything? Sometimes the label is just a jpg, sometimes very dense Illustrator files, or combination of both. So I can't just select and modify, I need to reduce the output of everything 20% of the K. Any help is appreciated.

{Renamed by MOD}

[Kurt Gold · Accepted solution]

You may try Edit > Edit Colours > Adjust Colours and decrease the Black setting there.

[Nooner911]

I went a step further and "select all" first, then edit colors. I didn't realize it could change the CMYK values on rastor images as well. This is exactly what I need to do. Thanks!

[DaveJCummings]

Glad Kurt could help 

[Ashutosh_Mishra]

Hi there,

Thanks for reaching out. I hope you found your answer.

We'd appreciate if you can mark the appropriate response correct. If you used any other method, you can share it with us. It'll help other users with similar concern.

I'd also recommend checking out this help article to know about adjusting colors in Illustrator.
Let us know if you have any other concern, we'll be happy to help.

Regards,

Ashutosh