The Stretch Contrast command automatically stretches the histogram values in the active layer. For each channel of the active layer, it finds the minimum and maximum values and uses them to stretch the Red, Green and Blue histograms to the full contrast range. The bright colors become brighter and the dark colors become darker, which increases the contrast. 「Stretch Contrast」 works on layers of RGB, Grayscale and Indexed images. Use 「Stretch Contrast」 only if you want to remove an undesirable color tint from an image which should contain pure white and pure black.

このコマンドは ホワイトバランス コマンドとも似ていますが、 非常に暗い画素も非常に明るい画素も退けないので白っぽい部分はあっても純白にならないことが多くあります。