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Opacity – The sum of the parts :huh:
#4
(10-21-2023, 07:26 PM)Krikor Wrote: I read the page with the indicated link, although it was instructive, it wasn't a very fun read. Even so, I expanded and found myself reading the part about Blend modes (provided by a link in 'See also').

Fortunately, I can use the tools in gimp without needing to have so much technical knowledge.

Ofnuts, thx!

Fun fact:

If you want to show the average of several layers, you stack them with an opacity of 1/N where N is the position in the stack, with 1 at the bottom. So from bottom, 100% (1/1), 50% (1/2), 33.3% (1/3), 25% (1/4), 20% (1/5).... A side effect of this rule is that if you want to average more layers, you just add them on top with adequate opacity without having to change the opacity of the layers already in the stack.

One the other hand, the "average" is the sum divided by the count... And what happens when you add red, green and blue? You get white. And when you divide the value of white? You get gray. And this is  indeed what you get when you stack the colors with the rule above:

   

PS: And in case you wonder why the gray value is 156, it happens to be the value of a gray that has the same average luminosity as a layer where 2/3 of the pixels are black and 1/3 are white...
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Messages In This Thread
RE: Opacity – The sum of the parts :huh: - by Ofnuts - 10-21-2023, 08:43 PM

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