Save render elements as Gamma 2.2 output?

[ShaunDon]

Hey all --

We've been using gamma correction for some time now and everyone here agrees that it's had a huge impact in our imagery. I've been very pleased at the speed that our work is rendering at now, since using the linear workflow you don't need to emit as much light in the scene as without.

I'm burning gamma into our saved files by setting our Gamma and LUT Preferences to 2.2 Output Gamma. So far this has worked fine for us, except now I have to composite some reflections in post requiring me to render layer elements.

So my bottom line issue is this: the full render and all the elements look perfect in the max frame buffer, but for whatever reason the elements are saving un-gamma corrected. When I boost the gamma in After Effects, the element passes are so dark to begin with that it introduces very noticable grain into my image. How can I get the elements to burn in the gamma the same way Max is burning it into the frame buffer image?

Appreciate the help as always!
Shaun

[tct70]

Hi Shaun,

Have you tried applying the gamma override as 2.2 when saving the elements individually.

Trev

[Shimakaze]

the frame buffers only display a preview of the gamma correction. to bake it into the saved output you need to use the gamma setting under color mapping. Also, I advice you to use the Vray Frame Buffer since it isn't affected by the gamma LUT settings and lets you see the color corrected version without having the gamma doubled. (to see the same gamma preview as in the max frame buffer all you have to do is click the sRGB button)
You might want to consider saving out to vrimg/exr instead though.

[ShaunDon]

Trev -- Gamma 2.2 in the render elements doubles the gamma in the frame buffer and gives me some really whacked out render element frames. Sorry I can't be more specific, but I see color blooms and other unusable craziness.

Shimakaze -- The frame buffer is burning in the gamma correction when I save the frames because I've set the Output Gamma to 2.2 in the Gamma and LUT max Preferences. But the render elements don't do the same. I've used the VRay frame buffer before, but it wants to save out a pre-gamma'd image which still needs to be adjusted in post.

I understand the benefits of not burning in gamma, but that simply is not an option here. Our projects are already pushing 20-30gb [edit:: make that 30-50gb!) without using a float file format like OpenEXR or VRimage, and we simply cannot afford the increase in file sizes. Burning the gamma has worked for us, it's just that the render elements don't want to save the same way...

Shaun

[Shimakaze]

The max frame buffer will always display based on the gamma LUT settings regardless, meaning if you change any other settings they will be doubled. that's not an error. In order to get the right result you have to set the gamma to 2.2 in the color mapping section of v-ray. If you then render to the max frame buffer it will appear as if it applied twice which is why using the vray frame buffer is recommended since it doesn't preview the Max gamma setting and so doesn't give false results. You can then save individual render elements by selecting them from the drop down list in the VFB or by selecting the save separate channels option in the vray settings.
What you see when using the V-Ray frame buffer is what you'll actually get (as long as you don't activate the sRGB button or any exposure controls) The gamma setting in the main Max preferences is just for preview purposes. It doesn't change how V-Ray works internally and the gamma is only applied when the picture reaches the Max Frame Buffer

[ShaunDon]

Thanks for the info, I'll have to play around with this after this project is finished. For now I've skipped the reflection compositing by including the elements in my render scene to reflect only.

Appreciate the input!
Shaun