GNOME Desktop users can put this in a Bash script in ~/.local/share/nautilus/ for more convincing looking fake PDF scans, accessible from your right-click menu. I do not recall where I copied it from originally to give credit so thanks, random internet person (probably on Stack Exchange). It works perfectly.
ROTATION=$(shuf -n 1 -e '-' '')$(shuf -n 1 -e $(seq 0.05 .5))
for pdf in "$@";
do magick -density 150 $pdf \
-linear-stretch '1.5%x2%' \
-rotate 0.4 \
-attenuate '0.01' \
+noise Multiplicative \
-colorspace 'gray' \
"${pdf%.*}-fakescan.${pdf##*.}"
done
That seq is probably supposed to be $(seq 0.05 0.05 0.5). Right now it's always 0.05.
Note that you can get random numbers straight from bash with $RANDOM. It's 15 bit (0 to 32767) but good enough here; this would get between 0.05 and 0.5: $(printf "0.%.4d\n" $((500 + RANDOM % 4501)))
You know, now that you point it out that seems obvious. I think maybe I was experimenting with rotation and left that in, unused. I did this years ago. The loop works OK though. Thanks for the feedback (and now I have to finish editing that script ...)