Clipped...

bodon

GDay all.

When you get time.  Still quite new to pixinsight but getting there.  One question bugs me all the time; what is meant by 'clipped' or 'clipped blacks'.  How do I know that I have 'clipped the blacks' in PI?

A too dark a background or an overstretch...

Appreciate your time

BlockHead

Yes.

If the original values in the image were 0.96, 0.9, and 0.95 ...and after you perform an operation they all become "1"...that is white clipping.  Same at the bottom end... where you make all values zeros. 

In some recent videos it is useful to create masks and adjust images to be clipped on purpose. This is called "thresholding" in my parlance. You know why? Because I say so! lol (It is because you are choosing a threshold above or below which something is desired or not.)

-the Blockhead

bodon

Thanks for the info.  Ta