Geoff Ghose wrote:
I apologize if this is a very basic question, but I'm really quite lost. I want an icc monitor profile that approximates linear input to luminance. (Yes, I realize that it can only be an approximation, and will suffer especially at low values).
Please read <http://www.argyllcms.com/doc/calvschar.html>. Now do you mean a profile or calibration ? A monitor profile doesn't give you any particular luminance, it characterizes the device (i.e. tells you what XYZ/D50 L*a*b* value you get for any RGB input).
So an RGB value of 128,128,128 is half the luminance of 255,255,255. (This are for visual psychophysics experiments).
Luminance defined in what space ? L*a*b* space ? Jab space ? XYZ space ? They will all be different.
I have tried setting target gamma to 1.0, but that really doesn't seem to do much of anything: when I run a report on the uncalibrated and calibrated monitors I get essentially the same gamma. My impression is that all the calibration is doing is trying to ensure that the color temperature is pretty consistent across input levels, but not remapping the input output relationship so as to significantly change gamma.
Sounds like you are talking about calibration. You can setup a calibration that maps RGB to L* using the dispcal -gl, but note that if you are interested in precisely what's going on, the non-zero nature of black on a real device will mess this up - see <http://www.argyllcms.com/doc/dispcal.html#g> Graeme Gill.