Vray VFB and saved image different

[LudvikKoutny]

Hi,

i recently noticed something very concerning. I am getting different output displayed in Vray VFB compared to saved JPEG. I double checked every setting, like Gamma in preferences, output gamma when saving, and color mapping settings, but everything seems to be in place.

This image shows the difference (i made a diagonal section between image obtained by screenshoting VFB and saved JPEG):


Here are my color mapping settings:


And my gamma settings:


The file has internally set input and output gamma to 2.2, like it should be in 3ds Max 2014+.

I am using Max 2014 with latest SP and Vray 3.00.07.

[LudvikKoutny]

Update:

I successfully managed to reproduce this problem on completely different computer with completely different scene, so it indeed seems to be a bug. Only thing these two computers had in common was 3ds Max and Vray version.

To reproduce it, render something darker. The problem mostly shows in darker areas.

[tashko.zashev]

Hi,

Would it be possible to attach your scene ? Just to be sure that we will use the same 3DS Max setup in our tests.

Edit: Actually I don't see any difference in the texture area, only at the background corners. Do you use any VFB color corrections ?

[LudvikKoutny]

Hi,

Would it be possible to attach your scene ? Just to be sure that we will use the same 3DS Max setup in our tests.

Edit: Actually I don't see any difference in the texture area, only at the background corners. Do you use any VFB color corrections ?

No, i do not (except sRGB of course),

and the difference is everywhere, i just picked bad image to demonstrate it on.

Here is the same scene, but the stone has just dark gray diffuse material without any textures. Top left part is VFB captured via screenshot, bottom right part is saved JPEG.

[vlado]

The V-Ray VFB displays the colors with sRGB color correction, which is what the sRGB standard is about. 3ds Max however saves the images with Gamma 2.2 correction. The two corrections are close, but are not the same and particularly with darker colors the difference may be visible.

Best regards,
Vlado

[LudvikKoutny]

The V-Ray VFB displays the colors with sRGB color correction, which is what the sRGB standard is about. 3ds Max however saves the images with Gamma 2.2 correction. The two corrections are close, but are not the same and particularly with darker colors the difference may be visible.

Best regards,
Vlado

Was it always like this? Because i do not recall ever noticing such thing in Vray 2.x releases.

And if this is really the case, i would suggest adding also Gamma 2.2 display mode to VFB in addition to sRGB and ICC profiles, because I can not imagine how can 21st century renderer not work in What You See Is What You Get fashion.

[LudvikKoutny]

Something like this perhaps:

[vlado]

Was it always like this?

Yes.

Because i do not recall ever noticing such thing in Vray 2.x releases.

<shrug> Other people have noticed LIke I said the difference is usually not that big.

And if this is really the case, i would suggest adding also Gamma 2.2 display mode to VFB in addition to sRGB and ICC profiles, because I can not imagine how can 21st century renderer not work in What You See Is What You Get fashion.

Gamma 2.2 is not standard, sRGB is the standard. If something has to change, why not fix the wrong place (i.e. the 3ds Max saver) instead of adding more confusion?

Best regards,
Vlado

[LudvikKoutny]

Good luck convincing Autodesk to get something right. Last time they touched input/output gamma, they managed to make loading of all bitmaps 9 times slower, and it took them half a year to fix it

[Morne]

Also, it depends on your monitor colour profile. If you loaded the disc that came with your monitor or did any kind of callibration or profiling to the monitor, then VFB will look different because Max does not read any colour profiles. (You can load an icc file into the VFB on the other hand)