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@andyrbell

andyrbell/scanner.sh

Last active October 8, 2025 07:32
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Make a pdf look scanned using ImageMagick
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scanner.sh
# use ImageMagick convert
# the order is important. the density argument applies to input.pdf and resize and rotate to output.pdf
convert -density 90 input.pdf -rotate 0.5 -attenuate 0.2 +noise Multiplicative -colorspace Gray output.pdf
@MartinDevillers
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For those on Windows make sure to install Ghostscript as well or else you'll get errors like

convert: FailedToExecuteCommand `"gswin32c.exe" -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 "-sDEVICE=pngalpha" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-r150x150"  "-sOutputFile=C:/Users/TURKEY~1/AppData/Local/Temp/magick-9420wtSmlrXSBcfh%d" "-fC:/Users/TURKEY~1/AppData/Local/Temp/magick-9420IJ2RKxHzcTQf" "-fC:/Users/TURKEY~1/AppData/Local/Temp/magick-9420t7VINjcK97Pq"' (The system cannot find the file specified.
) @ error/delegate.c/ExternalDelegateCommand/475.
convert: PDFDelegateFailed `The system cannot find the file specified.
' @ error/pdf.c/ReadPDFImage/662.

@restyler
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restyler commented Jan 3, 2022

thank you! I have used some of these commands to build https://oakpdf.com which not only applies scanner effect, but also allows to insert an image of signature or draw a signature.
My observations regarding -density parameter: 200 is good enough in most cases, while 300 gives ultimate quality - but the build time get catastrophically slow..

@EarlGeorge
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Great

@fewaltix
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fewaltix commented Mar 16, 2022 •
edited
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Thank you!
I used zenity to add graphical input and output prompts:
convert -density 150 "$(zenity --file-selection --title="Select Input File" --file-filter=*[PpDdFf])" -rotate "$([ $((RANDOM % 2)) -eq 1 ] && echo -)0.$(($RANDOM % 4 + 5))" -attenuate 0.4 +noise Multiplicative -attenuate 0.03 +noise Multiplicative -sharpen 0x1.0 -colorspace Gray "$(zenity --file-selection --save --title="Select Output File" --filename ".pdf")"

Can also be found here as a .desktop file, so the script can be started from the starter on Linux machines:
https://gist.github.com/fewaltix/c1437171d16671741aafe146751dbf9f

@leeeeeeeee2
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work

@mrnhrd
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mrnhrd commented Feb 14, 2025

On my ubuntu 20.04 machine this also added the PDF Metadata Tag producer=ImageMagick in the output. You might want to edit that out: https://askubuntu.com/questions/27381/how-to-edit-pdf-metadata-from-command-line

exiftool -Producer="" output.pdf

Using a realistic scanner name instead of the blank string is an exercise left for the reader 😛

@sophiebits
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If you want each page to be rotated by a different random amount, this worked for me:

magick -density 90 input.pdf -background white -seed 42 -rotate "%[fx:(u*2-1)*0.5]" -attenuate 0.2 +noise Multiplicative -colorspace Gray output.pdf

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