Brightness difference between images rendered locally versus renderfarm

[ruud3dv]

I'm struggling with a brightness difference between images rendered locally (left image) and images rendered on a renderfarm (in this case Rebusfarm, right image, darker).
Using V-Ray Adv 3.40.02 with 3dsMax 2016 x64 SP3, but have experienced this with earlier versions of V-Ray as well.

When outputting to vrimg and opening in Photoshop the images look identical, but JPG output with Frame buffer and Common Render Output shows the brightness difference. So something seems to go wrong when applying gamma/color correction?

Settings for color mapping are Vray default: Reinhard, with multiplier of 1 and burn of 1. No VFB color corrections, only activated 'Display colors in sRGB space'.
3ds Max Gamma is enabled, set to 2,2 and affects materials and colors.

Is there some hidden setting that affects my machine and isn't used on the renderfarm maybe?
I've included the test scene,does anyone have an idea what could cause this difference?

[ruud3dv]

Can someone please try to render the included scene (with Vray 3.40.02) and post the resulting jpg so I can compare it to the locally and renderfarm rendered images?
That way I can at least get an indication wether it's a local issue or a renderfarm issue.

[dlparisi]

Can someone please try to render the included scene (with Vray 3.40.02) and post the resulting jpg so I can compare it to the locally and renderfarm rendered images?
That way I can at least get an indication wether it's a local issue or a renderfarm issue.

I rendered it with the same versions as you (2016, 3.4.02) and and got identical results to your first image (local). The rebus farm version was darker.

[ruud3dv]

Thanks for testing, the problem doesn't seem to be on my end then.
Unfortunately Rebusfarm doesn't know what could cause the difference either... anyone any ideas?

[LudvikKoutny]

Any chance you touched any of the color correction settings in V-Ray VFB?

[ruud3dv]

Nope, no color corrections in VFB or effects, mostly default V-Ray settings.
An entirely new scene with all default V-Ray settings (without GI) gave the same difference.

[tashko.zashev]

I have seen similar difference in buckets in DR renderings due to different Windows regional settings.
Just an assumption.

[ruud3dv]

If difference in regional settings is the problem, could it be that the gamma is applied wrong then? For instance 2 instead of 2.2 when commas are used instead of period as decimal separator for example. Ie: the number after the comma would be discarded then.
I suspect the gamma because 16/32 bit output doesn't seem to have the brightness difference.

Did a quick test and it indeed looks like a gamma of 2 is applied instead of 2.2, causing the output to be a bit too dark. Gamma correction on the Rebusfarm 8-bit output of 1.1 (2.2 / 2.0) results in a correct image.

[svetlozar.draganov]

This has nothing to do with V-Ray, it is totally on Autodesk/3dsMax side.
Regional settings affects 3dsMax decimal values and this should be considered as very important factor when rendering on multiple machines.
Same regional settings should be used across all the machines, otherwise discrepancies are almost always guaranteed.