USAGE: colortemp [-t temperatures] [infile] outfile
USAGE: colortemp [-h or -help]

-t ... temperture(s) .... t1[,t2]; 1000 to 40000 deg K
......................... t1=desired temperature; t2=current temperature;
......................... t2 default=pure white (near 6500)
-f ... fov .............. fov=field of view for observation;
......................... fov=2 or 10 deg; default=2
infile outfile .......... if no infile and no temperature provided, then
......................... outfile will be a color vs temperature chart;
......................... if no infile but t1 provided, then outfile
......................... will be a color swatch for the provided temperture;
......................... if infile and t1[,t2] provided, then infile will
......................... be color transformed to generate the outfile
......................... according to the temperture(s) provided

PURPOSE: To transform and image's overall color balance according to a desired color temperature change.

DESCRIPTION: COLORTEMP transforms an image's overall color balance according to a desired color temperature change. If no infile and no temperature is provided, the script will generate a color vs temperature chart. If no infile is provided, but a desired temperature is specified, then the script will generate a color swatch for the specified temperature.

ARGUMENTS:

-t temperature(s) ... TEMPERATURE(S) specifies the desired (t1) temperature and the current (t2) temperature. Values range from 1000 to 40,000 deg K. The default for t2 is pure white which is near 6500 deg K.

-f fov ... FOV is the observer's field of view. Allowed values are fov=2 or 10 deg. The default is 2. Differences in color temperature are slight between the two.

infile outfile ... If no infile and no temperature are provided, then outfile will be a color vs temperature chart. If no infile but t1 is provided, then outfile will be a color swatch for the provided temperture. If infile and t1[,t2] provided, then infile will be color transformed to generate the outfile according to temperture(s) provided.

Requires NetPBM (http://netpbm.sourceforge.net/)

CAVEAT: No guarantee that this script will work on all platforms, nor that trapping of inconsistent parameters is complete and foolproof. Use At Your Own Risk.

Some Common Illumination Color Temperatures
See http://www.etconsult.com/papers/whitepoint.pdf