surface shader texture gamma bug?

[sharktacos]

I'm working in linear (gamma 2.2, linear workflow checked, convert to sRGB for RenderView on).

If I apply an image map to a vRayMtl it displays correctly.

However if I apply that same image to a Maya Surface Shader it is not being linearized (ie it appears washed out) and I need to manually insert a gamma node set to .454 to compensate.

Is that a bug?

What I am trying to do is return a flat matte texture without lighting.

I have also tried
a) putting the image in the incandescence of a Lambert
b) putting the image in the color of a VrayLightMtl

Same thing, washed out yucky gamma.

[djx]

"linear workflow" checkbox is not intended for general use. It is for quickly setting up old scenes that were not originally created with proper linear workflow, but even then it only works for fileTextures connected to colorcentric things in vrayMtl.
It is better to leave "linear workflow" unchecked. Then in your fileTextures node, go to the Attributes menu and add the vray "bitmap input gamma" attribute, which will default to the correct setting for linear workflow. Do this for all of your textures that are used for color.

[sharktacos]

"linear workflow" checkbox is not intended for general use. It is for quickly setting up old scenes that were not originally created with proper linear workflow, but even then it only works for fileTextures connected to colorcentric things in vrayMtl.
It is better to leave "linear workflow" unchecked. Then in your fileTextures node, go to the Attributes menu and add the vray "bitmap input gamma" attribute, which will default to the correct setting for linear workflow. Do this for all of your textures that are used for color.

I know that manual says that the linear button is "not intended to replace linear workflow" but that is just crazy. No one wants to manually add gamma corrections to hundreds of textures in a scene. This is the whole reason that Maya 2011 has the new color management system, (which I think Max has had for a while). So despite what the Vray manual says, I think the linear checkbox should be used generally (as in all the time) for LWF to bypass the tedious and unnecessary task of doing this manually which surely no one enjoys. The only thing that this would not work for of course is color swatches, but then again neither does a gamma correction node. I see no visual disadvantage, and a huge time advantage in using it.

In this particular case what does not make much sense is that the same image when applied to the diffuse color of a VrayMtl (or of a Blinn) is just fine. It is only washed out for the SurfaceShader, which makes me think there may be a problem in how the SurfaceShader was implemented into Vray which seems to treat it as a light (incandescence) rather than a flat color (ambient).

[djx]

Its actually not that tedious if you do it at the same time as browsing for the image file. One extra menu click. If the attribute was added automatically when you make the fileTexture node you would have to remember to turn it off for bump maps etc. But I have considered trying to hack the AETemplate to add the "bitmap input gamma" automatically.
I don't hate the way it is now though.

[sharktacos]

What is curious to me is that with the bitmap input gamma it works fine in the SurfaceShader. This makes me conclude that Vray assumes that the surface shader should be considered a light and act in the same way as a VrayLightMaterial would where the assumption is that I will be putting an HDR image into the color slot which should not get a degamma since it is already linear. So the linear button is trying to be smart about that and not degamma images going into lights. So let me change my question a bit:

If I want to have a matte shader texture (flat Maya ambient) which would be commonly used in production for things like projection matte paintings and stand in objects for live action integration, is there a Vray node that is intended for this purpose? Because it seems that the Surface Shader in Vray-land is not.