[Bf-compositor] use alpha premultiplication in linear Color Space?

[Ton Roosendaal]

Hi,

"Fade" can mean too many things.
You mean: "Image should become transparent - during an alpha-over operation"?

Well to start with - such effects look much different in linear, than in non-linear spaces.

And realize: premultiplied RGBA = alpha should not be changed. Not!
Straight alpha - yes, that you can do with what you like.

-Ton-

--------------------------------------------------------
Ton Roosendaal  -  ton at blender.org   -   www.blender.org
Chairman Blender Foundation - Producer Blender Institute
Entrepotdok 57A  -  1018AD Amsterdam  -  The Netherlands



On 4 Apr, 2014, at 13:25, Francesco Paglia wrote:

> Hi, hope I used a right title for this topic.
> I've just setup a simple nodegroup to make a fade node.
> Here the tree:
> 
> https://lh4.googleusercontent.com/-Mos7IL6bx4E/Uz6VHnKqZ3I/AAAAAAAAI1U/zJJ7zOFnRWQ/w1176-h368-no/fade_nodesetup.png
> 
> As input of this group I've a renderlayer, if I'm not wrong the compositor works with a linear workflow so why I have to add make alpha straight at the beginning and a premultiply at the end to make it working properly?
> 
> Thanks for your help
> Francesco
> 
> -- 
> Francesco Paglia
> Vfx and Production Supervisor
> 
> mobile  +39 347.82.12.473
> e-mail   f.paglia.80 at gmail.com
> 
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