ColorFormat.TintAndShade Property (Excel)
Returns or sets a Single that lightens or darkens a color.
You can enter a number from -1 (darkest) to 1 (lightest) for the TintAndShade property. Zero (0) is neutral.
Attempting to set this property to a value less than -1 or more than 1 results in a run-time error: "The specified value is out of range." This property works for both theme colors and nontheme colors.