3ds max Vray-Gamma confusion

#1

gamma
gamma.jpg2000x1800 1.86 MB

Hi Guys,
I’m bit confused with a project I’m working on. Please Refer the image attached. One of the renders is where the gamma curve(or sRGB) in VFB render window is on (which is coming too bright) and the other where the gamma curve(or sRGB) in VFB render window is off(which is coming too dark).
The scene only has a vray sun with intensity 0.1 and vray sky with intensity 1.0.
The scene is still work in progress. I’m not sure whether i should go ahead with lighting in this scene by refering the gamma curve VFB on or off.

Color mapping type : Linear Multiply
Gamma is set to 2.2
Mode : color mapping only(no gamma)

I think the scene which is only lit by a vraysun(intensity 0.1) and vray sky shouldnt have this much overall brightness in reality, so i should leave gamma curve in VFB window off. But I generally see people leave the gamma curve(or sRGB) in VFB window on.

Also, as a seperate query when i import jpgs for displacement maps should i change anything?
Need some help.
Thanks

#2

It should be on always in the framebuffer. It’s not a choice, but a correct display. They only reason you shouldn’t if in your gamma preference (customize - preferences) settings you have your gamma baked in as 2.2.
You usually leave it as 1.0 in preferences, because the best output is in linear gamma (1.0), and then to apply 2.2 just to preview. In compositing apps you apply 2.2. after any color operations as a viering node. The reason to use 1.0 for any compositing is that the math will be correct. With 2.2 baked in it’s all screwed.
Gamma is a complicated subject, because it has to do both with monitor gamma, which is kind of the opposite of gamma 2.2 curve, so you compensate it by applying it over. And most images have that gamma already applied via co-called profiles.
If you want to make it darker, use exposure control or post-processing.
So in a nutshell, 2.2 in framebuffer preview, 1.0 for gamma output (saving images, preferrably in openexr). Then opening it with 1.0 gamma, applying color operations, and using 2.2 gamma node for correction in compositing software.
If you use photoshop, you are limited to working with wrong color math anyway, so you can make it 2.2 in preferences and turn off in the framebuffer. But it’s a bad idea generally.

#3

Thanks…although I set my gamma in customize preferences to 2.2 …so I should work with GB curve off I guess.

#4

If your preferences gamma is 2.2, your vfb gamma should be off, otherwise it will double it.