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I am working on a project to measure the various components of light in a night scene and need to stack and average multiple images. I am doing this using layers in GIMP 2.10.8 and hope to reduce the opacity of each stacked layer; eg 100%, 50%, 33%, etc. However in a simple test using just two layers (Black, 0.000, at 100% opacity and above that White, 1.000 at 50% opacity) the resulting "visible layer" pixels had a value of 0.737 not the 0.500 I had expected. I am not sure what I am doing wrong but would appreciate any advice on how to stack say 10 photographic images which gives equal weight to the pixel values in each image?
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02-27-2019, 09:43 PM
(This post was last modified: 02-27-2019, 09:46 PM by Bob.
Edit Reason: Pasted image did not work
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Thank you Ofnuts. Selecting under "Precision", "Linear Light" gives me in Color Picker the very pixel values I need ...but I note the adjacent RGB (%) figures are not then correct. Presumably a bug? Big thanks for your help.
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Maybe I was a bit premature in giving this the tick off. I found the exported images still use "Perceptive Gamma" pixel values even when "Linear Light" is ticked in Image / Precision or in Edit / Preferences /Gamma. Something to watch for if you are into stacking images and then using the pixel values.
