When you use transparency, ID switches to a more accurate screen preview. How does the page look in Overprint preview?
Overprint preview didn't stop the lightening of the photo.
A google search turned up the suggestion to change the transparency blend space to RGB, which worked in InDesign. When I make the pdf (no color conversion) it looks ok. But when turning on Output Preview in Acrobat, the photo lightens again. Weird and frustrating - I'm not sure what the final output will look like.
Is Transparency Flattener set at High res an option?
I appreciate your help!
I didn't expect the overprint preview to stop the lightening, I expected it to show lighter in ID when it was turned on becasue that is how it is expected to print.
I have the feeling that your PDF settings aren't preserving transparency. Try exporting to Acrobat 5 or higher compatibility so the transparency remains live, but I don't think that's going to make a difference.