Hi,
I have been using InDesign for some time now, and I am encountering a problem I can't seem to fix with my own brain, in spite of my many attempts.
I usually export my InDesign works as .pdf, often using the highest quality (standard presets) and I have never had any problem.
Today, I've experienced the strangest thing.
My InDesign documents uses margins, like red waves. The .jpeg image is set into a template (a master spread).
The final document contains 30+ pages and everything is displayed nicely when in InDesign.
Then I export.
The first 4 pages have their margins with the right color (as displayed in InDesign), but after, the margins and globaly all the colors are a little bit washed out, a little grayed.
I tried to export again, thinking there was an error during the process, but I get the exact same result.
I tried to export with other presets, I change the quality from High to middle, then export.
Tada, now, the first 4 pages are washed out and the other pages have the right color.
Here is a screenshot (poor quality, because of the free upload service).

The color on the left is supposed to be the good one, the color on the right is the washed out / grayed color.
I have tried for an hour now to play with some export setting conscerning colors, but I don't get the right result.
I would gladly appreciate if any experienced user have any advice or clue concerning this issue.
I use InDesign at my school, CS5 version on a Mac running OS10.7
Hoping to hearing from anyone,
Regards,