Yes, you can do that with photo editing programs, which often have scripting ("batch processing") features so you can do it repeatedly. Depending on the quality of the source material it may be hard to get right, though. One technique that's useful in dealing with colors in the way you want to is to convert the images to "Lab" (or "L*a*b") format, as opposed to RGB or CMYK. That separates the brightness information from the red/green and yellow/blue distinctions, and lets you apply curves, or threshold operations, or things like that to emphasize colors or force them to particular values. It will take experimenting with your particular source material to figure out the way. If standard programs don't do the job, an image file manipulation library might be the way to get at this. paul

On 2018-03-20 7:50 AM, Mattis Lind via cctalk wrote: Matt Zucker's noteshrink is designed for similar tasks. I've had good results, even on whole books: https://github.com/mzucker/noteshrink Feel free to send me your original files if you'd like me to try things out.