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1.0 Gamma - Linearized Working Space?

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Max Jackson
1.0 Gamma - Linearized Working Space?
on Nov 2, 2010 at 9:11:09 am

Hello CC,

Mr. Christiansen in his book says that, and I quote..."Once you discover the truth about working linearized with 1.0 gamma, you understand that Screen is a workaround..."

What is 1.0 gamma? I looked it up on Wikipedia and found this:

Okay, so gamma is..."the name of a nonlinear operation used to code and decode luminance".

I've seen the word 'linear' used twice. So in terms of 'linear' operation...from what perspective are we talking about in regards to blending modes, in particular Screen?

Sorry if this is in the wrong forum. I did a search for Gamma 1.0 and nothing came up. Google was piping me into software kernels. ?

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Todd Kopriva
Re: 1.0 Gamma - Linearized Working Space?
on Nov 2, 2010 at 4:14:14 pm

This question doesn't belong in the basics forum.

This page has information about gamma, including gamma of 1.0 (linear tone response).

Todd Kopriva, Adobe Systems Incorporated
Technical Support for professional video software
After Effects Help & Support
Premiere Pro Help & Support

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Max Jackson
Re: 1.0 Gamma - Linearized Working Space?
on Nov 2, 2010 at 5:11:51 pm

Okay, anything I have to read twice I'll be sure to post in the main forum.

As I understanding it, operating in linear light is operating with a gamma value of one. The reason being, working with any exponent value of light is then multiplied by one which equals itself, hence – linear. Anything not 1.0 is considered perceptual and not absolute.

That being said using Screen which has a formula of 1-((1-A) * (1-B)) is well...A whole lot of ones...multiplying +/- which behaves a lot the same (identical multiplication) from the sound of it. That is unlike Add which is A+B.

The result in applying a Screen mode is light values remain blending transparency without additional "light".

Am I warm?

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