Hi June,
Excel is limited to 56 colors (colorindex colors), you can
specify colors using RGB, but Excel will try to match the
color you specify to one of the 56 colors in your color
palette. You would be much better choosing your color via
the colorindex. More information on Colors in
Color Palette and the 56 Excel ColorIndex Colors
http://www.mvps.org/dmcritchie/excel/colors.htm
Selection.Interior.Color = RGB(200, 250, 200)
Selection.Interior.Color = &Hc8efac8
but you would be better off selecting a colorindex yourself
Selection.Interior.ColorIndex = 35 ' RGB(204,255,204)
as they don't always work out close to what you want.