Weird color distortion when using an effect on top of an image in InDesign

Question

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!

Answer 1

I figured it out (naturally, after I submitted the question)! The problem was that I had my Transparency Blend Space set to "Document CMYK" instead of "Document RGB". Now the bright pink is showing up regardless of what I throw on top of it, and the bright pink shows up within InDesign as well.

You can change your Transparency Blend Space by going to the Edit > Transparency Blend Space submenu.

I hope this helps whoever else is having the same problem!

Answer 2

You don't need to worry about whether you are in CMYK or RGB, just right-click on the gradient/overlayed object and select Effects > Transparency. Set the blend mode as Multiply.

This will appear to add the colors together instead of subtracting them, which is what results in the dirty gray look (lack of color) you are trying to avoid.