Frame Buffer Saving Issues

[shane_oshea]

Hello folks! I have a few questions. Whenever I am working in my frame buffer, it defaults to a display correction of sRGB.

I noticed there is also a display correction for Gamma 2.2...

Toggling between these two in the VFB setting yield different results.


When I save out the image from my frame buffer.... even when pointed on sRGB Display Correction, it saves as the Gamma 2.2 version. On top of that I get... *almost* the same look as Gamma 2.2 in but it's slightly more lifted.



Similar discrepancy to above, I can copy from the clip board when in sRGB mode and get a close to sRGB result but with the same offset in shadow darkness as we see in the above comparison.




So some questions..
1. What is the difference between srgb and gamma 2.2 display corrections?
2. Which one should I be working in as a good standard/best practice?
3. Why do I default to Display Corrections in sRGB if they default save as Gamma 2.2?
4. Why is there a subtle lift in shadow quality, between my frame buffer versus when saved? (Tried saving as multiple file formats to rule out.)
5. Is there a more practical way to save my image as it appears in the sRGB Display Correction than Copying to my clip board and pasting into Photoshop?

My goal is to get the sRGB version as it looks is the VFB, so save in an image file and look like a 1:1. I'm loosing too much localized contrast for my liking and don't quite understand why there's these discrepancies.

Thanks for your brains!

Other useful context: On Vray 5.2.3 & Max 2022.

I can provide the .vrimg file if that's helpful.

[hermit.crab]

1. What is the difference between srgb and gamma 2.2 display corrections?

Read more here.

2. Which one should I be working in as a good standard/best practice?

Depends on the screen, on which the image is going to be viewed. Most screens are calibrated for the sRGB standard.

3. Why do I default to Display Corrections in sRGB if they default save as Gamma 2.2?

Not all image formats are saved with baked gamma (linear images). And since linear images are more of an industry standard, that's why.

4. Why is there a subtle lift in shadow quality, between my frame buffer versus when saved? (Tried saving as multiple file formats to rule out.)

Precisely because of the difference between sRGB and Gamma 2.2. Judging by your next question, you're saving are .jpgs, where gamma is baked.

5. Is there a more practical way to save my image as it appears in the sRGB Display Correction than Copying to my clip board and pasting into Photoshop?

Yes, saving linear images from the V-Ray output options. This way the image is the same and you only need to match the display corrections between the softwares.

[MartinDarzacq]

Thank you for the links. For what I understood and tried, the only way to export the render as same as vfb is:

1-srgb display in frame buffer
2-saving it as .exr
3-then exporting as .jpg 8bit fom photoshop

Am I correct here? or is there a way, a more user-friendly setting somewhere, to save a jpeg straight from the Vfb (without getting the baked 2.2 gamma)?

[hermit.crab]

Thank you for the links. For what I understood and tried, the only way to export the render as same as vfb is:

1-srgb display in frame buffer
2-saving it as .exr
3-then exporting as .jpg 8bit fom photoshop

Am I correct here? or is there a way, a more user-friendly setting somewhere, to save a jpeg straight from the Vfb (without getting the baked 2.2 gamma)?

You can always override the Gamma saving to 1 in the Save dialogue. Check screencap.

[MartinDarzacq]

I did try hat, sadly, this is how it ends up:
->from vfb to jpeg: render looks like vfb display gamma 2.2
->from vfb to EXR 32bit to jpeg 8bit: render looks like vfb display sRGB

->from vfb to jpeg with gamma override set at 1: the render looks completely different compare to vfb, way darker and under exposed

[hermit.crab]

->from vfb to jpeg: render looks like vfb display gamma 2.2

We discussed this already. 3ds Max always applies a gamma 2.2 curve not a sRGB one.

->from vfb to jpeg with gamma override set at 1: the render looks completely different compare to vfb, way darker and under exposed

Normal. The point here was to apply an sRGB curve in post.

->from vfb to EXR 32bit to jpeg 8bit: render looks like vfb display sRGB

This works, of course.

[Crayox13]

Has this been solved? I'm just testing things, and in VFB my colours are more saturated than after I open a saved jpg. Not enough to warrant a gamma difference. Like VFB just shows them differently.

I tried screen capturing VFB, and that made it look as if I saved a jpg. So weird! I do have a hardware calibrated screen, could that be the reason?

[hermit.crab]

Has this been solved? I'm just testing things, and in VFB my colours are more saturated than after I open a saved jpg. Not enough to warrant a gamma difference. Like VFB just shows them differently.

I tried screen capturing VFB, and that made it look as if I saved a jpg. So weird! I do have a hardware calibrated screen, could that be the reason?

The VFB shows 32-bit color depth, whereas jpgs are only 8-bit.