Use of the histogram in "Envisage" (Continuation)

Another comand which we did not use: Histogram "sliders".
The upper one sets the level of the black. In other words, it allow to indicate the value under which the pixels will be "extinct".
This will be translated on the image by a reinforcement of the dark zones. Used with delicacy this can increase the image quality. With excess obviously it will destroy most of the details in the dark zones.
The removed part is materialized by a black area which is superimposed on the green curve.

The bottom slider controls the level of the "white". The principle is the same as above... but reversed ;o)
The part of the histogram removed is materialized in white...!

By combining the two sliders (with moderation) we can obtain a "visual" improvement of the image.

ATTENTION !! however by thus making, the luminosity scale of the recorded images will be reduced. As an example here below, instead of the 65535 levels allowed by the 16bits, only 17873 of them are used.

Personally I prefer to record the images with the maximum scale of luminosity. I thus leave the two cursors on their extrem value (0 for the black and 65535 for the white). Thus I have a larger latitude for the post processing.
However if one wants to use the function "Combine" of the software "Envisage" it will be necessary to adjust the thresholds for an optimum result.

Good hunting! ... I mean "stars hunting" ;o)...