washed out gamma correcton 2,2

[cristoforo]

I've been reading alot about this gamma correction that I previously never used. Though, I feel like the images become very washed out. In an exterior scene the shadows lose depth becoming too light. Is all this normal? All I am doing is applying the gamma correcton of 2,2 in the color mapping and also have enabled the gamma / LUT correcton in the preferences and input gamma 2,2 and output 1 for bitmaps.

[rivoli]

applying the curve correction it's not enough, when you start to work linear lights and above all materials must be adjusted accordingly. taking a scene which is not made for a linear workflow and simply correct the gamma won't work. well, you'll quite likely to get the results you're describing

[flino2004]

if your output is HDR or EXR you don't need to have 2.2 color mapping...press srgb botton under vray frame buffer and you would see how it looks like.
keep 2.2 in input gamma...textures for bumps, displacement(grayscale) or normalmaps so far i know thay have to be gamma 1.

[rivoli]

if your output is HDR or EXR you don't need to have 2.2 color mapping...press srgb botton under vray frame buffer and you would see how it looks like.

well, not really. you indeed have to let vray know that you're rendering with a gamma correction when working linearly, and saving to linear formats. otherwise it won't be doing the correct sampling as you would expect. what you can do is check "don't affect colours" and use the srgb button as a preview in the vray fb.

but all this doesn't have anything to do with washed out outputs, when working linearly it's very important to build scenes specifically for the workflow.
here's a link to an old but still very informative thread, in case you missed it:

http://www.chaosgroup.com/forums/vbu...ad.php?t=36359

[flino2004]

if you don't check " don't affect color" you get gamma 2.2 baked twice, right?

[rivoli]

basically, yes. you'll have a linear file with a backed gamma correction, as if you had double corrected it.

[pixela]

Rivoli :

I feel a little confused about this.
Let me try to explain my question:

When working on a NEW scene,
I set my gamma value 2.2 and makes all input gamma for all bitmaps as 2.2.
And then I start to create my materials.
But I always get very poor contrast too. So at the end I gave up working with LWF.

But as far as I understand, now I read that you say, it should be totally a different workflow apart from setting up gamma values.
What do you mean with this?
Thnaks a lot.

[rivoli]

actually the idea behind lfw it's quite simple, it just started as an inverse gamma curve correction. of course any gamma adjustment to an image can drastically change its look, if working linearly was only a matter of adjusting gamma, than I guess one would hardly need any workflow. if that was the case one could simply render an image and then do the correction in post. which would, of course, result in badly sampled, awfully desaturated, totally wrong images.
apart from all gamma settings in max, which are there only for previewing purposes, if one wants to do any kind of lfw, the way materials behaves and reacts to lights must be taken into account accordingly.
usually you end up with much darker materials and bitmaps, once you start to compensate for the linear adjustment and take into consideration the fact that in real life materials are way less reflective than what you may intuitively think. this has been discussed several times, there's an ongoing thread which is quite interesting at the moment:

http://www.chaosgroup.com/forums/vbu...ad.php?t=47243

it links to other threads and posts which in turn point to other discussions.. there's quite a bit of reading that one can do, if willing to do so, of course but I guess the information out there is definitely worthwhile.

[pixela]

Thank you very much for this thread! It seems very interesting