MobileRead Forums - View Single Post - Dealing with white text on colored background when prepping PDFs for grayscale or B&W

rkomar · 10-26-2025, 11:06 AM

This is a tough but interesting problem. After some googling, I came upon a python implementation of the algorithm produced by Grundland and Dodgson (https://github.com/damondpham/decolorize-RGB2grayscale). I haven't tried it, but it looks promising. It probably doesn't do anything about saving toner, so maybe you can make simple adjustments first before converting the image with this algorithm. Good luck!

10-26-2025, 11:06 AM	#3
rkomar Wizard Posts: 3,065 Karma: 18821071 Join Date: Oct 2010 Location: Sudbury, ON, Canada Device: PRS-505, PB 902, PRS-T1, PB 623, PB 840, PB 633	This is a tough but interesting problem. After some googling, I came upon a python implementation of the algorithm produced by Grundland and Dodgson (https://github.com/damondpham/decolorize-RGB2grayscale). I haven't tried it, but it looks promising. It probably doesn't do anything about saving toner, so maybe you can make simple adjustments first before converting the image with this algorithm. Good luck!