Hi There,
Arnold is here. It’s super easy to use with Maya’s Color Management System.
Just use the default settings (forget the gamma nodes).
A Simple guide to Color Space settings in file nodes:
- Set Color Space to sRGB for textures which are directly responsible for colors.
(For example: Diffuse Color, Specular Color, Reflection Color, Refraction Color, Transmittance.) - Set Color Space to RAW for textures which contain non surface color information.
(For example: Roughness, Opacity, Bump Map, Normal Map, Displacement Map, IOR.)
As simple as that.
Automatic .tx conversion is also great (“on” by default).
Cheers, D
Denes Dankhazi's Blogfolio 
wow that not helpful at all
Not helpful? That is the most important information about basic color management. What would be helpful for you? Please, share with us.
there is a difference between the Arnold version for Maya 2016 and the Arnold version for Maya 2017. I’m not getting the same results with the same image opened in both versions. The 2016 version seems to be much easier for me to adjust the gamma and to get the color results that I want, the 2017 version is not giving me the color results that I want at all! It’s quite frustrating to say the least!
If you use the color management system correctly you’ll get the same results.
Of course if you set custom gamma values for one or two textures, the results will be different.
Can you be more specific why did you do that?
Could you send me some images or a simple scene?
You can still use the old method in Maya 2017 with Arnold if you want.
I have a big problem i try to add the same texture to the color and the bump do i need to set the color space sRGB or raw
In that case use sRGB because the color more important and bump form that color is not a nice thing to do anyway (not real bump data but simple, I get it).
Or in this case use a gamma node with 0.454 to linearize it for bump.
Or you can duplicate the file node and set it differently.
thanks a lot