If you save a 32-bit per channel (HDR) PSD file:
There is no gamma correction applied to anything by psd-manager itself. Photoshop expects a 32-bit (HDR) file to have a linear color profile (which means Gamma needs to be 1.0). Photoshop will show you the colors corrected for your display if you have enabled View > Proof Colors, so you will see the image adjusted.
In the V-ray Color mapping rollout you should set Gamma to 2.2 and enable Don't Affect Colors (adaptation only). This tells V-ray that you will later want to display the image using a Gamma of 2.2 (like on a typical sRGB monitor) but will not actually bake the color correction into the pixels. So you are setup for whats called a linear workflow this way.
If you save an 8 or 16 -bit per channel PSD file:
psd-manager uses the Gamma options set in the 3ds max Preferences dialog. So if you have setup an 3ds max output gamma of 2.2 then this is what psd-manager will use. However there are important exceptions to that:
Per default there is no gamma correction applied to render elements, only to the main render output (and layers using RenderCutout mode). This is important because otherwise render elements would not match the look of the main render when combined. So in Photoshop you will typically add an Exposure Adjustment layer on top of your render elements layer stack to correct the Gamma (to match the rest of the file).
If you don't want psd-manager to apply Gamma correction for some reason then you can turn it off in the psd-manager Advanced Options dialog (Gear Icon button in psd-manager).
Recommended typical setup for V-Ray:
V-ray Color mapping rollout:
- Gamma: 2.2
- Don't Affect Colors: on
- Linear workflow: off (this is an old option in V-ray, you have a true linear workflow without it)
3ds max Preferences > Gamma LUT:
- Enable Gamma correction: on
- Input Gamma & Display Gamma & Output Gamma: all set to 2.2
Your V-ray setup:
If you set Gamma in V-Ray Color Mapping to 1.0 that would be fine for saving 32-bit PSD, and also fine for saving 8/16 bit PSDs if your 3ds max Output Gamma is set to 2.2. But it would help the V-Ray renderer if you set the V-Ray Gamma to 2.2 and turn Don't Affect colors: on. V-ray will then spend more time calculating detail in darker areas instead but not actually do a gamma correction to the color values. So this is better than you having to fix it it by cranking up other V-Ray options for the whole scene to counteract lacking precision in dark areas that becomes visible when displaying the image using a sRGB working space.
If you set Gamma in V-Ray Color Mapping to 2.2 and you have Don't Affect Colors turned off, then you would get a double gamma correction if your 3ds max Output Gamma is set to 2.2, because psd-manager will use this value for its gamma correction and apply it on top (just like it happens if you save using the 3ds max VFB with the same options).