Re: [Gimp-user] selection by value threshold

On 07/10/17 08:33, Mitti Mithai wrote:
Gimp 2.9 loads by 16-bit astrophotography files either TIF or FITS just

I've never had to to this with gimp yet, but I need to make a selection by
value threshold (I want to "cut out" stars that are hitting saturation in
my image with values of 64k)...I can't quite seem to figure out how to do
it.  Does anyone have any advice?
Quick and dirty:

- open the channels list
- drag any of the RGB channels down to the lsti to below to make a copy
- treshold the copy
- channel to selection

Slightly more accurate:

- Create grayscale copy of layer (Color>Desaturate (lightness)
- Threshold to your liking
- While it is visible, open the channel list, right click any R,G,B channel and "Channel to selection"

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