VFB not accurate

[devin]

I'm using Vray 3.50.04 for Max and I've begun to use the correction controls through the VFB and immediately I can see a big difference between what I'm seeing in the VFB and what's being saved out. Initially I thought this might be because I was saving the image as an 8 bit Jpeg but saving out a 16 bit Tiff results in the same image. The VFB image has exposure, hue/saturation and curve adjustments and the image is very saturated with lots of contrast, once saved out the image is somewhat flat with much less tonality. I've tried doing a screen shot to capture the VFB to show how big the difference is but it doesn't work. Is this a known problem, what's the point of having the correction controls if you can't save the output correctly?

[^Lele^]

It depends on how you're saving the image.
"Save current Channel" from the vfb toolbar saves all the CCs as well.

[devin]

Hi Lele,
I'm saving out using the "save current channel" option from the VFB.

[^Lele^]

Try a ctrl+c on the VFB, that should copy the image as is in the windows clipboard.

[devin]

The image copied does look slightly better than the one saved but it's still far from what the VFB is showing.

[^Lele^]

This is wrong: they both should (and do here) look identical.
Do you have some 3rd party color management tool active?

[devin]

No, the only plugin I'm using is Forest Pro.

[^Lele^]

I'm running fast out of ideas...
Display Gamma couldn't be (whatever is in the vfb gets captured like a standard screen capture with ctrl+c).
The only thing i'm left with is the tool you use to display the saved images: it may add a gamma you had off in the viewer (although, paste in mspaint to be sure of what you see.)

[devin]

I'm using Photoshop but ill try Paint.

[^Lele^]

Oh, then yes, it could be any number of color modes in Photoshop, please try to see if Paint does it right...

[padre.ayuso]

Hmmmm, thought here. Could it be how the monitor displays colors? Different programs have different display modes. I have a similar problem with Camera Raw displaying differently than what Photoshop does, even though they are using the same program??? I know there are solutions out there, but I have not figured out the exact combination of settings. I know it also has to do with how the graphics card displays colors through the monitor and through the programs you are using to view the images. I don't think it is a VRay issue, but if you figure it out, let me know. And if I figure out the solution to my problem, I'll post it, as I think they may be related somehow.

[devin]

I have a high end factory calibrated monitor and a Quadro 6000 card, it running on Windows 7 with Max 2016. I don't think its a program problem because when I turn off all the correction controlls and save the image looks the same in the VFB & Photoshop. I also don't think Photoshop is applying a strange color profile for the same reason.

[padre.ayuso]

OK... high end color corrected monitor. Maybe Lele can see if this would also apply. I found the following on the Corona website, it may not apply to VRay, but then again, it might!

https://corona-renderer.com/forum/in...?topic=13592.0

[devin]

How do we find out if Vray is doing this?

[^Lele^]

I have a high end factory calibrated monitor and a Quadro 6000 card, it running on Windows 7 with Max 2016. I don't think its a program problem because when I turn off all the correction controlls and save the image looks the same in the VFB & Photoshop. I also don't think Photoshop is applying a strange color profile for the same reason.

Ah-ah! so it only happens when you apply CC to the render, but not when you save the image as plain?
If that is the case, it could be us, but it'd also likely be something well noticed, and it's the first i hear of it, (and have yet to witness...).
Did Paint open the unmanaged image right, though?
Do you by chance also have an OCIO descriptr applied, or a LUT, in the VFB?
I have been saving the heck out of the VFB, with severe CC, opened in anything i could (affinity, nuke, fusion, mspaint, but no photoshop), no issue, not a third decimal difference, as expected.
I can only work with numbers, feel free to send me two such different pictures, assuming, at this point, that they are indeed different in data.