First Steps with Argyll and ColorHug

In April of 2012 I bought a ColorHug colorimeter. I got a bit discouraged when the first thing I realized was that one of my monitors needed replacing, and put the the colorhug in a drawer until today.

With quite a lot of help and encouragment from Pascal de Bruijn, I finally got it going. Pascal has written an informative blog post on color management. That's a good place to look for background. This is more of a "write down the commands so I don't forget" sort of blog post, but it might help somebody else trying to calibrate their monitor using argyll on the command line. I'm not running gnome, so using gnome color manager turns out to be a bit of a hassle.

I run Debian Wheezy on this machine, and I'll mention the packages I used, even though I didn't install most of them today.

Find the masking tape, and tear off a long enough strip to hold the ColorHug on the monitor. This is probably the real reason I gave up last time; it takes about 45minutes to run the calibration, and I lack the attention span/upper-arm-strength to hold the sensor up for that long. Apparently new ColorHugs are shipping with some elastic.
Update the firmware on the colorhug. This is a gui-wizard kindof thing.
```
 % apt-get install colorhug-client
 % colorhug-flash 
```
Set the monitor to factory defaults. On this ASUS PA238QR, that is brightness 100, contrast 80, R=G=B=100. I adjusted the brightness down to about 70; 100 is kindof eye-burning IMHO.
Figure out which display is which; I have two monitors.
```
 % dispwin -\?
```
Look under "-d n"

Do the calibration. This is really verbatim from Pascal, except I added the ENABLE_COLORHUG=true and -d 2 bits.

 % apt-get install argyll
 % ENABLE_COLORHUG=true dispcal -v -d 2 -m -q m -y l -t 6500 -g 2.2 test
 % targen -v -d 3 -G -f 128 test
 % ENABLE_COLORHUG=true dispread -v -d 2 -y l -k test.cal test
 % colprof -v -A "make" -M "model" -D "make model desc" -C   "copyright" -q m -a G test

Load the profile
```
 % dispwin -d 2 -I test.icc           
```
It seems this only loads the x property _ICC_PROFILE_1 instead of _ICC_PROFILE; whether this works for a particular application seems to be not 100% guaranteed. It seems ok for darktable and gimp.