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Gets or sets the tint and shade value of the interior pattern.
Use this property to read how the current pattern color is lightened or darkened. The valid number is from -1 (darkest) to 1 (lightest). Zero (0) is neutral.
double PatternTintAndShade { get; set; }
Property PatternTintAndShade As Double
IRange cell = worksheet.Range["A1"];
cell.Interior.Pattern = Pattern.LightDown;
cell.Interior.PatternThemeColor = ThemeColor.Accent1;
cell.Interior.PatternTintAndShade = 0.25;
double patternTintAndShade = cell.Interior.PatternTintAndShade;