On 13.06.19 16:29, k. jantzen wrote: > > in general I do not have a problem reading a pdf file with either xpdf or > documentviewer.
Yup, documentviewer will sometimes show faint lines better, I find, but it's easy to set the background colour in xpdf. > But once in a while I get a pdf file that they cannot read and then I have > to go to Windows to open it. > > What is so spectacular about these files that they cannot be read by the > above mentioned programs? That varies, and a reader with good error messages is the easiest way to find out. > Is there another program that would read such a file? Well, given s/would/could, try mupdf: $ apt-cache search mupdf mupdf - lightweight PDF viewer mupdf-tools - commmand line tools for the MuPDF viewer libmupdf-dev - development files for the MuPDF viewer In my case, a pdf certificate from a state authority displayed the logo and signature in xpdf, but none of the text - not much use at all. A quick install of mupdf not only allowed the whole document to be displayed, but issued (a squillion times) the following error message on stderr: Error: Couldn't create a font for 'ABCDEE+Calibri,Bold' Error: Found a bad table definition on true type definition, trying to continue... after an initial: Error: PDF file is damaged - attempting to reconstruct xref table... I only use mupdf for problem pdf files, but it's very nifty to have on hand. Erik