davidrevoy, 2 months ago

@nekohayo I use a target, the IT8 7/2 1993 from http://www.targets.coloraid.de/ , then calibration: http://www.argyllcms.com/doc/Scenarios.html#PS1 , after that you'll get an ICC profile. I then scan with a shortcut keyboard to a script (Win+S , setup in Plasma):

#!/bin/bash
version=$(date +%Y-%m-%d_%Hh%Mm%Ss)
output=$HOME/pictures/screenshots/${version}_scanner_raw.png
scanimage -p --device "genesys" -l 0 -t 0 -x 210 -y 297 --resolution 600 --calibration-file /home/<user>/pathToYour.icc --mode Color --format=png > ${output}

cJ, 2 months ago

@nekohayo

I hope by now there's more user and developer-friendly tooling, and I want to know, but a dozen years ago after going nuts trying to twist argyllcms for my needs (fisheye) I wasn't convinced and decided to roll my own and I've been using my tooling since then, for everything. I image a color target, then patches are localized, sampled, and a "profile" is created so as to remap the original colors to that color space so they're "optimal".

In your case, it seems that GNOME simple-scan should already assign a profile to your files if the device has an ICC profile (but documentation is pending... https://gitlab.gnome.org/GNOME/simple-scan/-/issues/222) and you should be able to calibrate your scanner with your hardware and a target.

nekohayo, 2 months ago

@cJ @hub
So presumably I need to buy the "RF" target (?) from http://www.targets.coloraid.de, then use the commandline to get a calibration, throw it at DisplayCal, then throw it at XSane or GIMP?

Turns out there's a calibration button for scanners in GNOME Control Center, which… calls a G-C-M feature that was completely removed. What a sad state of affairs this is.

Wondering if there are plans to solve this with the color-managed #Wayland effort, I filed this problem summary: https://gitlab.freedesktop.org/pq/color-and-hdr/-/issues/33

hub, 2 months ago

@nekohayo you need a target. Something calibrated you scan, and use as reference for the output to build the profile.

nekohayo, 2 months ago

@hub OK, presumably one can just get the lots-of-ratings 60$ target swatch from Amazon and whatnot… but what about the calibration+scanning software on Linux? Do we even have such a tool chain? My googlefu has failed me so far.

I'm crossing fingers that it is not a case of "nope, there is nothing, gotta use Windows with the scanner manufacturer's software plus some expensive specialized scanning software"…