Boolean value.

In this case, the component values of each pixel will be preserved (within the limits of precision) even though their effective ranges may be different. For example, if you have a 16bpp grayscale image but each pixel value actually only ranges from 0-255, and you want 0 to represent black and 255 to represent white, it makes sense to set this option to true and avoid scaling the values. If scaling were used in such a case, the image would appear black since the brightest possible value (255) would be scaled down to almost nothing: (255/65535) * 255 = 1.