So, I'm in comic publishing. I was sent a pdf that is missing the linework entirely when opened in acrobat reader (not pro). Other layers, like the text and color layer, are still visible. A couple times when I opened the file, I saw the line work for a split second before it disapeared. I've tried "show/hide - navigation panes -layers" and there's nothing in there to turn off or on. I've tried sending the pdf as if I were going to print it and make a new flattened file, but that didn't fix it either (read that tip somewhere else). I can't think of what else to try. This isn't something I've encountered before. Is something wrong on my end or an export issue on the publishers end?
Can you check the document Properties to see what program made the file? I'm wondering if a blending mode is kicking in a split second after the file opens.
It was made in InDesign
If you want to post the PDF file for us to look at it would be a lot easier than all this guessing.
Have you contacted the persons that made the PDF? They should inspect the file and try creating an new PDF.
(Line art is typically put in Multiply mode on top of the coloring layers.)
Also see Uwe Laubender's suggestions below.
how are the Reader's preferences set?
Page Display > Use Overprint Preview:
If not set to "Always", change that to "Always".
Page Display > Page Content and Information >
[ x ] Show large images
If this is not checked, enable the control.
( ACP )
Not all layers are shown in the "Layers" panel.
try running this code in the console window. It displays all layers in the panel.
You'll find a video here on using the console window.