I have A0 poster with 2 science images that were taken by a spacecraft. On top of it I have graphs and some text. When I print it as A4 pdf on my office small printer - the colors are fine. When I print it as A0 on my university poster printer the colors are bad in multiple ways - over saturated, faded and etc. However, the text and graphs that I added on top of the images are totally fine! I work in Adobe Illustrator CMYK format of course! Help!
P.s. I have had a few step (compression, cropping) in Adobe Photoshop if that matters at all. Poster printer is HP DesignJet Z2100 Photo Printer.