ABSTRACT
Stretching causes a linear image to become non-linear and certain specialist image manipulation tools are optimized for linear images. These generally fix problems in the original files such as background gradients, color balance and convolution. Color management is a science in its own right. Some imaging tools automatically distinguish between these entities; others need a little help in the form of a mask. Masks are incredibly useful and vary slightly depending upon their application. A star mask is a special image file that is used selectively to protect parts of the image from being affected by the imaging tool. It is either binary or, more usefully, has varying degrees of protection with smooth boundaries between different protected and unprotected areas to disguise its application. The luminance information provides the bite to an image. RGB or color processing deviates from luminance processing in two ways; color calibration and sharpening.
