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That's not really a PDF thing. In that case the PDF is a thin wrapper around raster images. Extract the images, increase the contrast with gimp or imagemagick
by jacob019 2y ago
That's not really a PDF thing. In that case the PDF is a thin wrapper around raster images. Extract the images, increase the contrast with gimp or imagemagick, and make a new PDF. You could script this if you had a lot of them.