In Acrobat try turning off the 'enhance thin lines' option under preferences>display
Sounds like you have some sort of transparency (transparent .png ?) on those pages (the white lines are a transparency flattening artifact known as stitching). It's a known problem that ID "emboldens" type on screen when it interacts with transparency, and it often shows in low resolution printing (desktop printers, commercial copiers) as well.
Make sure the text is in front of everything else to minimize the problem, but it probably will not go away. You can add transparency to all pages to make them look the same.
Hi, thank you for replying so quickly
Well, you pointed out something I didn't notice, but that's right, the "embolding" is only happening on pages that don't have a png image on them.
Well, I don't really care if it is a little bolder on every page, but I do mind having different thicknesses on different pages.. I want all pages to look the same
How do I add transparency to every page ?
Put a transparent object on the edge of the master page where it will be out of the way.
I created an empty (transparent) image in GIMP of 100x100px and added it to every page corner of my file. Works like a charm, everything looks great now ! No more embolding !
THANK YOU so much for you help, greatly appreciated !