USAGE: tricolorize [-l lcolor] [-m mcolor] [-h hcolor] [-c contrast] [-o offset] [-t type] infile outfile [lutfile]
USAGE: tricolorize [-l lcolor] [-m mcolor] [-h hcolor] [-c contrast] [-o offset] [-t type] lutfile
USAGE: tricolorize [-help]

-l .... lcolor ........... Color for low end of grayscale; Any valid IM color is allowed;
.......................... The default=black
-m .... mcolor ........... Color for mid range of grayscale; Any valid IM color is allowed;
.......................... The default=gray50
-h .... hcolor ........... Color for high end of grayscale; Any valid IM color is allowed;
.......................... The default=white
-c .... contrast ......... percent contrast change; integers; -100<=contrast<=100; default=0
-o .... offset ........... percent color offset; integers; -100<=offset<=100; default=0
-t .... type ............. Type of look up table (lut) smoothing/interpolation; choices are:
.......................... cubic, quadratic, gaussian, triangle, point; default=triangle

PURPOSE: To smoothly colorize a grayscale image with either one, two or three different colors.

DESCRIPTION: TRICOLORIZE smoothly colorizes a grayscale image with either one, two or three different colors. If the input image is color, it will be converted to grayscale first. Using an appropriate mid color with low color of black and high color of white will allow one to tint an image. This achieves the same result as my tricolorize script, except the default type there is quadratic. The script generates a color look up table (lut) and applies it against the grayscale version of the image. The lut can be saved, if desired, for future use and will have a size of 256x20 pixels.

ARGUMENTS:

-l lcolor ... LCOLOR is the color to use at the low end of the grayscale. The default=black. Any valid IM color is allowed. See http://imagemagick.org/script/color.php

-m mcolor ... MCOLOR is the color to use in the mid grayscale range. The default=gray50. Any valid IM color is allowed. See http://imagemagick.org/script/color.php For tinting, a good choice of colors may be specified as hsl with saturation about 25% and lightness about 50% and your choice of hue in range 0 to 360 degrees. For reference, see http://homepages.cwi.nl/~steven/css/hsl-examples.html

-h hcolor ... HCOLOR is the color to use at the high end of the grayscale. The default=white. Any valid IM color is allowed. See http://imagemagick.org/script/color.php

-c contrast ... CONTRAST is the percent change in color contrast. Values are integers such that -100<=contrast<=100. The default=0.

-o offset ... OFFSET is the percent shift of the colors in the lut. Values are integers such that -100<=offset<=100. Positive values shift the colors towards the brighter end of the grayscale and negative values shift the colors towards the darker end of the grayscale. The default=0.

-t type ... TYPE of smoothing/interpolation of the colors to fill out the look up table. The choices are: cubic, gaussian, quadratic, triangle and point. The default=triangle.

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.