Display Gammacorrection

[Lord Futzi Voldemort]

Turning Display Gamma Correction on for UI Widgets (Color Sliders etc.) seems to turn of any other Display Gamma Correction if it´s on (Preview, Region, Shaderballs)

Is this correct?

And mapping a sRGB Texture as color on a constant shader, needs to get loaded as linear to display and render correctly, without any Display Gamma Correction on (Nonlinear workflow)

Is this behavior normal? I have to load the rendered output as linear in nuke too, even if it is saved as sRGB.
Also, if I load a sRGB texture as sRGB I need to apply display gamma in the pass rendersetting, though I don´t have no display gamma activated, to be able to load it as sRGB in nuke, but the my preview would be way to dark. That´s somehow weird....

Achim

Edit:
I think I got the sRGB thing. Setting the clip to linear means mr leaves gamma untouched, and setting it to sRGB means mr removes the gamma, which would be wrong for a nonlinear workflow. So when i set the clip to sRGB, mr removes the gamma and and reapplies it when I check "apply display gamma" in the pass settings. Is that correct?

The first issue however remains....

[Maximus]

The options in the color management preferences:Render regions, Render Pass and Preview, Shader Balls, UI Widgets; are only for display purpose they dont write any file in hard disk, they are used to allow you to choos which way you like to work.

What i do is this:

Check shaderballs and UI Widgtets only in preferences (this is because i need to see the correct color in 2.2 when shading)
I dont use Render regions and Render pass and preview option, because in every work i do i always use a Mia_Photographic_exposure wich i use to control the final output gamma.

In the Preferences "Rendering -> Image" I have the color profile set to "Automatic".

Now having this setup, everything depends on 1) mia photographic exposure 2) the option "Apply Display Gamma Correction" in the output ppg of render manager.

If i need my render in Linear to be composite later, i just leave the mia_photographic exposure with gamma 1 and render the file
If i dont need the render to be composited and i can just render out in gamma 2.2 already i use the mia_photographic exposure at 2.2.
Last note, the option "apply display gamma correction" wont be displayed in your preview or render region renders, that happen only when you write the file to disk.

[Lord Futzi Voldemort]

Yes, the purpose of the display gamma, is clear, I was confused by the colorprofile thing which is only of use if you have actuallyhave a linear workflow. It´s not that obvious after all. One might think, if you load sRGB, it should be set to sRGB anytime and if you check "apply display gamma" the actual sRGB gamma is applied which you don´t have to set somewhere.

Only I found out (you may check that too) that when I have display gamma for say render region on, have an active render region open, and check then in the preferences "ui widgets", display gamma for the active region is turned off (the check mark still is set for region) and it has no influence on the widgets. This has nothing to do with what I render or save, I think it may be a bug.

Anyway, I prefer the "apply display gamma" method as default, since having display gamma corrected for the region may collide with the tonemapper when you render a region in the cameraview.

Achim

[Rork]

It seems there's still a lot of confusion about the LWF workflow.

You might have seen these already, but again:

http://kobayashystips.blogspot.com/2009 ... image.html
http://rowu-media.nl/content/prive/tuto ... Gamma.html

And the manual says it a lot in the "Data Management > Managing Image Sources & Clips" and "Preference Reference > General Preferences > Display Preferences" section.

And to answer some of your answers:

I think I got the sRGB thing. Setting the clip to linear means mr leaves gamma untouched, and setting it to sRGB means mr removes the gamma, which would be wrong for a nonlinear workflow. So when i set the clip to sRGB, mr removes the gamma and and reapplies it when I check "apply display gamma" in the pass settings. Is that correct?

You're sentences are contradicting each other, first assumption of wrong is wrong, second about gamma is not.

The clip management set to sRGB will 'tell' MR it's an 8/16 bit image with 2.2 gamma applied to it, as all sRGB images are, and 'strip' that gamma from the image to bring it into the linear 'world' for rendering usage. When using a LWF workflow (Color Management turned on) this is the proper way to go. Be aware of the fact when one brings in a 32 bit image (.exr or .hdr), you'll have to set the clip management back to linear, or MR will try to adjust an already linear image. Leaving you with undesirable results.
This is also the case for black&white gradients, displacement- and bump maps. Treat them as linear files, or even better, make them 32 bit files.

When finally rendering the pass, you can turn on that "apply display gamma" checkbox to 'burn' the gamma back into the final image.
This because we were only -viewing- a gamma corrected image on the screen. If you don't do this, you'll get a very dark image, which need 2.2 gamma again to bring it back as you saw it in the region or preview.

Personally I advise against that workflow, as you don't have any control anymore on the gamma after rendering. For compositing purposes leave the checkbox unchecked, and play with gamma in the FXTree or any other proper compositor (no, not Photoshop......)

Only I found out (you may check that too) that when I have display gamma for say render region on, have an active render region open, and check then in the preferences "ui widgets", display gamma for the active region is turned off (the check mark still is set for region) and it has no influence on the widgets. This has nothing to do with what I render or save, I think it may be a bug.

I've seen that before, not in 2012 yet. It looks like a bug or refresh issue on the region. Sometimes you needed to restart SI to get it working.

Anyway, I prefer the "apply display gamma" method as default, since having display gamma corrected for the region may collide with the tonemapper when you render a region in the cameraview.

Be careful with that, using a full LWF workflow (all Color Management boxes turned on) doesn't need a tonemapper or vice versa. Different workflows. Read Maximus's workflow again on this.

rob