On Thursday, 10 December 2020 15:21:05 GMT Grant Edwards wrote:
> On 2020-12-10, Michael <confabulate@kintzios.com> wrote:
> > On Thursday, 10 December 2020 08:27:33 GMT Neil Bothwick wrote:
> [...]
> 
> >> I use gscan2pdf, although it sans to many more file formats. Scan to  2
> >> page PDF and your printer can print in duplex.
> >> 
> >> Gscan2pdf has lots of nice features, I used to use it with an ADF and it
> >> would scan all the sheets, then I'd turn the stack over and feed it back
> >> in and it would scan the other sides and then put all the pages in the
> >> correct order.
> >> 
> >> I have a duplex scanner now, but that was a real time saver.
> > 
> > Alternatively, on the CLI you could use imagemagick to convert your png,
> > tiff, jpg, etc., to pdf:
> > 
> > convert scan1.png scan1.pdf
> > convert scan2.png scan2.pdf
> > 
> > Then join the two pdf documents into one with two pages, using poppler's
> > pdfunite:
> > 
> > pdfunite scan1.pdf scan2.pdf scanned.pdf
> 
> There's no need for the two-step process:
> 
> $ convert scan1.png scan2.png scanned.pdf
> 
> --
> Grant

There was some vulnerability in ghostscript[1] which disabled the above 
conversion - but I can't find the BGO number.  I thought it had been patched 
since then, but my system appears to not have been fixed:

$ convert scan1.jpg scan2.jpg scan.pdf
convert: attempt to perform an operation not allowed by the security policy 
`PDF' @ error/constitute.c/IsCoderAuthorized/422.

[1] https://www.kb.cert.org/vuls/id/332928/