Ok sorry for all the bad writting, I was doing on my phone in bed late last night... could not sleep.
🙂Anyway, let me try again:
If you have scene linear material also known as linear light material, and your final output you want to apply a gamma 2.2 or sRGB so it looks correct when viewed in the computer. Follow these steps:
1. load the material with a image import node.
2. since there is nothing to remove gamma wise, no need to add anything.
3. put a sRGB node (if that is what you want) prior to the output node.
4. Do all your work
5. Then render as normal then the material will come out with gamma 2.2 applied.
The issue I am trying to address is when you want to work with nodes and you are not viewing the output node in the player view, you will see your material in scene linear mode, to see it with the sRGB you need to apply a vLUT or ViewLUT to the display passthrough. This will, and you watched my video, so you know what is going on, apply the sRGB gamma curve to the image without actually effecting the image. It is just a way to view your material with a LUT. The problem comes when you want to view the output nodes which is after the sRGB node which is effecting your material. You then see a double gamma. If you mute the sRGB while you are working then everything will look fine and be correct, when you are ready to output your composition, just turn on the sRGB node again and it will render out your material with the correct gamma and all is good!
Now if you have material being loaded into your composition that had a gamma already on it, like a digital photograph, you can go to the options tab on the image import node and you can set it there to remove the gamma. It then converts the material to scene linear and then you just follow the rest of the above and it will work as expected.
Hope that helps.
cheers
Mark Rasmussen
VFX - Supervisor | Compositor
Enigma|FX
TOXIK/Composite BLOG
http://enigmafx.ca/efxblog