[CentOS] Changing Color Mappings

I have been tasked with finding a way to change the color mappings on a CentOS 5.2 system. Basically I want to make an image that is black and white appear in different shades of gray by adjusting the color mappings. I need to know the starting point for the color maps however so I can make the appropriate adjustments. I have been told this should be some kind of look up table array of 256x3 elements. I have searched through the frame buffer in the kernel and the driver area for the intel frame buffer but haven't found anything that looks appropriate. Does this table exist or is the problem being tackled completely wrong.

Any help, ideas, or pointers would be greatly appreciated.

Thanks in advance.

Brian