In Adobe InDesign, I have placed a pink image that I brought in from Photoshop. The below screenshot is how the pink looks like in Mac Preview (I'm on Mountain Lion).
I wanted to add some lines to that background, so I whipped something up in Illustrator. The result was as I expected:
But then I decided to turn down the opacity of the stripes. All of a sudden, the exported PDF has a much darker and subdued pink background:
I then removed the transparency effect, and the bright pink came right back. I later found that if I applied any effect to an element on top of my pink background, the pink changes from "bright pink" to "dark pink". Why is this the case? I don't know if this is related, but in InDesign, the pink is dark as well. When I export it as a PDF, however, the bright pink comes back (and looks the same as in the PSD file).
Any help on this matter would be greatly appreciated!