submenu contains operations which
automatically adjust the distribution of colors in the active layer,
without requiring any input from the user. Several of these operations
are actually implemented as plugins.
8.6.2. Automatic Color-Stretching
GIMP has several automatic commands for stretching
the columns of the histogram for the color channels of the active layer.
By pushing bright pixels to the right and dark pixels to the left, they
make bright pixels brighter and dark pixels darker, which enhances the
contrast in the layer.
Some of the commands stretch the three color channels equally, so that
the hues are not changed. Other commands stretch each of the color
channels separately, which changes the hues.
The way the stretching is done varies with the different commands and
the results look different. It is not easy to predict exactly what each
command will do. If you know exactly what you are doing, you can get the
same results, and even more, with the
Here are examples of the results of these commands, all together on one
page, so you can compare them more easily. The most appropriate command
depends upon your image, so you should try each of them to see which
command works best on it.
The original layer and its histograms