To Dream of Magick

Color Multipliers

Savanni D'Gerinel 29 Sep, 2014

I hacked out a small GTK utility last night. The problem, and this really only applies to Linux, is that the Sony NEX-series cameras don’t record the color temperature and green/magenta balance in the exif data. They do, however, record an RGGB line like so:

WB RGGB Levels                  : 2068 1024 1024 2160


ufraw on Linux doesn’t recognize this. With a couple of experiments I figured out what these values mean and how to translate them into something useful for ufraw. And then I reinvented it too many times and finally decided to encode it into an application.

color-temp will, given the string above, calculate out the RGB multipliers that UFraw uses for developing a raw file. I have placeholders there for color temperature and green/magenta balance (which is isomorphic to the RGB multipliers, but friendlier in some ways), but that is tricky to calculate and I haven’t succeeded at that yet.

I’m working on getting the application packaged, and when I do I’ll make a debian package available for download. Until then, just snag and build the code:

color-temp$cabal install --dependencies-only color-temp$ cabal install
anywhere\$ color-temp


And then just paste the RGGB levels (2068 1024 1024 2160) into the RGGB field.

Dreamer, Shaper, Seeker, Maker