When you have a 32-bit color value, you can convert it to a grey-scale – that is, you can determine how it would appear on a monochromatic display (more or less) using the following function:

Function GetGreyScale(ByVal lColor As Long)    lColor = 0.33 * (lColor Mod 256) + 0.59 * ((lColor  256) Mod 256) + 0.11 * _        ((lColor  65536) Mod 256)    GetGreyScale = RGB(lColor, lColor, lColor)End Function