gamma correction tables

[allenb@cs.uoregon.edu]

Has anyone out there played with the gamma correction tables?  I want to write
some Lisp functions that will blank the screen without changing the color
tables.  I want to transfer and/or draw images to the screen and control the
time that the image is visible.  When drawing or copying is too slow you can
see the image being painted.  It looks like the gamma correction tables will
allow me to turn the screen black while painting the image and then allow a
timed exposure.  Any help or examples will be appreciated.

Allen