I'm having problems with darker colors in my PDFs when I print them. I'm working on a catalogue and the prices (numbers in red) are becoming "transparent" when there is a dark(er) color behind them.
I have taken two photos showing the problem (files attached). As shown, the red text becomes transparent and shows whatever is behind. It only happens when it's a darker color (notice "109" in Photo 1 how it doesn't happen where there is a light background behind it).
Tried printing it in .PNG and that is no problem. The actual PDF-file preview does not show any transparency either.
Do you see the problem with Overprint Preview turned on? It looks like you might have the text’s red fill set to Overprint. Select the text and open the Attributes panel to check.
"Overprint fill" is checked, but I don't see any difference in-document (live preview or w.e) when I uncheck.
Having it checked would cause the problem you are seeing in print. To view overprints in InDesign you have to turn on Overprint or Separation Preview. If the red color is RGB, the overprint might not show in InDesign, but could in Acrobat if you made the conversion to CMYK on the PDF export.
In Acrobat there is a Page Display preference for showing overprints, or you can preview them in the Output Preview panel. In any case select the red text, uncheck OP, and try exporting and printing again.
Also, PNG and JPEG Exports have a Simulate Overprint checkbox