What I have done on some sistems is to have a Color reference
I set some textboxes (you can use other control like shape), with a color and a tooltip
that shows the meaning of the color on grids. Then you can set a color on columns, rows or cells
has you want with a value returned from Function or a Method call with the value passed as parameter
Hope this help
Mauricio
Be fast like the Fox
Be free like the Penguin
Se Rápido como el Zorro
Se libre como el Pingüino