In order to prevent image data from being destroyed, a special control curve is created that is attached to the image. It may be used to create the desired special effects.
It is possible that pre-SL96 control curves may conflict with a
newly created one. Naturally, the older control curves are not lost
– they're just utilized in different ways: First, a histogram is
created that is based on the data. When the settings are concluded,
this control curve is extracted from the image and merged with the
histogram control curve. The new control curve is applied to the image
and alters its appearance accordingly. The Histogram module
remembers
the old control curve and, if desired, re-applies in
to the image.
Only through this, admittedly rather complex, control curve operation is it possible to modify an image in the Histogram module without permanently altering or even destroying it. Naturally, the individual control curves can be freely changed or removed.
