PDA

View Full Version : Vray Linear workflow Texture Gamma

qup
06-27-2011, 10:21 PM
hey so quick question, i know this has been up before but it seem my problem is opposite everyone elses.. so hope i can get a quick reply on this one..

I save my textures out of Photoshop in PSD format, and add them to my VRay materials as PSD's and when i render my scene, all the textures are really dark and what seems really really saturated.. how should i correct this? im using Nederhorst settings for rendering.

should i use a differnet file format out of phtoshop instead of PSD's. I'd rather not use EXR's out of photoshop as that would include installing plugins on all the computers here at work and render farm etc.

so how do i render my textures out of VRay so they look like they do within Photoshop?

the only way i can seem to fix it, which doesnt seem to be the right way to do it - is to save the texture as a Tif out of PS, add it to my VRay material, and go to Attribute - add texture gamma correction and set it to 0.6

hope someone can help
much appriciate it.
Adam
Taunise
06-28-2011, 01:36 AM
Ok, I'm not 100% sure with VRay because I've never used it, but Maya linear workflow is thus:

Everything in Maya is linear, the shaders, lights etc. However, your textures are corrected to aproximately gamma 2.2 by default (what everything works in).

In order to fix this, you need to attach some sort of lens shader to your camera and set the gamma on it to 2.2, now you will be seeing your scene in gamma 2.2.

Then what you do, is attach a gammacorrect node between your textures and the slot where you're putting them (only diffuse, don't do this to bump maps or normals or anything), and set each channel (r g and b) to .455 which is the approximate correction you need in order to get your 2.2 image to appear as a 1.0 image.

Now your maya scene is all at gamma 1.0, and your lens shader set to 2.2 lets you see what's going on when you render. When you are ready to output your final linear file, simply delete the 2.2 lens shader.

Note, there are some discrepencies. I've noticed Maya's exrs from mental ray at 1.0 brought into nuke and corrected do NOT look the same as a 2.2 render brought straight in as a 2.2 render in nuke, and I've had to use colour correct nodes to adjust.

Now I'm not sure if that answers your question or not :)

I'll pop a clearer workflow on my blog in the next few days, this is a confusing issue.
CGTalk Moderation
06-28-2011, 01:36 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.