Reply To: Index and transparency questions

Jongware said:

As for #2., Word internally converts a lot of bitmap files to the PNG format, which allows transparency. InDesign does not check if it's actually used (it would need to check each separate pixel for that), so when it encounters a PNG file that declares “I might have some transparent pixels” it assumes it has.

Transparent items force InDesign to use a slower-but-more-accurate drawing model. Unfortunately, this is also reflected in text rendering, which seems to be a bit bolder than usual. However, usually it's not visible in print. (Caveat: this actually depends on the stacking order of text and transparent items.)

As you noted, the effect disappears when you “flatten” the images (I assume you do this with Photoshop?), and thus remove the transparency. That is indeed a solution.

Another would be to force InDesign to flatten out transparency on exporting your PDF, and there are various ways of doing this. Export using one of the “pre-press” PDF-X presets (I always forget which one 'cause I do the next thing, which is…) or use a Very Old PDF version such as 1.4, which doesn't support transparency natively. You can also tinker with the transparecy settings inside InDesign itself.

In general I avoid the problem in its entirety by never using natively embedded Word objects. I convert everything to either a bitmap file on its own, or to a ready-to-be-placed PDF. Little more work, way better control over quality.