impress grey slide

what is happening here



It’s really annoying, and I don’t even know why, so I don’t know what to search for

Without the document it is very hard to investigate. Please reduce the document (remove slides) as far as possible, but so that the problem is still visible, and provide a download. (I guess, it is a wrong set image filter. But without document…)

Since it’s a university document, I don’t think I can legally put it here. It’s on every slide. At first I though it was something like read-only, but I can modify. And when I try to copy the text and I select it, it keeps that grey thing. Picture on fist post

I have seen differences between pptx and odp in the interpretation of image filters. I mean the settings from the “Picture” toolbar, especially the sublist “Color”. For LibreOffice the values should all be 0, but 1.0 for Gamma. Another think to do: Unpack the original file and look, whether the original pictures are correct. Same for file saved with LO. I think of pictures, because the slides look as if they use a background picture.

Could you post a ODP without content? What is happening on the “Master slide”? Also, it looks like the background changes between slides 8 and 9 in the second screenshot; have you tried removing any background? (For diagnostic purposes, at least!)

I unselected “display the master background” and it’s gone, but I have to do it for every slide. I made the background as blank and it worked
Guess the teachers do stuff differently in some pp
thanks

It looks like a moiré effect, so perhaps the master slide has a texture / pattern in the background?