srg and linear srg options reversed Tweet

[boxfx]

Since octane 2020.2.4 the setting: "Render settings > octane render > main > color space" has had sRGB and linear sRGB reversed. All my srgb renders are coming out pale and washed out with linear colour space and all my linear srgb renders are coming out as darker. This is only since updating from 2020.2 to 2020.2.4

This also seems affected by switching from premultiplied alphas + keep background and straight alphas + not keeping background

project attached

win 10
c4d r20.059
geforce 3090
driver 466.47

[boxfx]

Any update on this?

[aoktar]

Update? I can't see anything wrong. Linear sRGB is always darker against normal sRGB.

[boxfx]

There's literally a faulty project and a series of images illustrating the problem, how fan you possibly say this is how its supposed to work?

Why does an sRGB render with a straight alpha look completely different from one with a premultiplied alpha? The only difference should be the slight fringe around the outside.

Why does every project render differently in version 2020.2.4 compared to 2020.2?

srgb.mp4 screen capture with narration attached

[aoktar]

Well, I didn't get which parameter you was talking about. Capture makes it clearer. Will check why it happens

[aoktar]

After checking a little bit, it's about color profile change if you select "straight alpha". Your sRGB image profile internally becomes "linear" in the case. In new color management system of plug the thing is a bit complicated.
There's a few things to work-around: using LDR-8bit render buffer or using a different image format with linear profiling. Not sure If I can bring a safe solution for that in future.

[aoktar]

After checking a little bit, it's about color profile change if you select "straight alpha". Your sRGB image profile internally becomes "linear" in the case. In new color management system of plug the thing is a bit complicated.
There's a few things to work-around: using LDR-8bit render buffer or using a different image format with linear profiling. Not sure If I can bring a safe solution for that in future.

[Gpix]

Yep, i can confirm this, and it bugged me a lot in the last clients' projects I used to have rendered also last year with same render setting without any gamma difference issue and now seeing suddenly faded out bright EXR-Renders after 10 hours of a nightly rendering shift and than deleting 20 Hi-Res-Renderings because they had been faulty

Since the mentioned update, the final rendered image in the picture viewer has a different gamma with the same settings used in previous versions of the octane 2020.2.4 plug-in.
The Live-Viewer is in my workflow always set to HDR/sRgb. The Octane Camera is set to "Linear" and Gamma to 2.2.

I use to render the output file as a 32-bit *.EXR-File.

I tried a little around and checked every possible combination to match the outcome of the Cinema 4D Picture Viewer and Octane's Live Viewer.

To get the exact same result in the saved EXR-File, you have to change in the Octane Render Main Settings under SETTINGS now the color space to Linear sRGB and check on "Force Tone Mapping". Then the output is the exact same as seen and worked on in the live viewer.

Didn't try out with Alpha-Channel, but even without, the plugin shows that behaviour.

Why did that behaviour change in the plugin with the 2020.2.4 version? And was there a note anywhere in the changelog, that would have made us professional users aware that we have to change something in our render settings with the plugin since 2020.2.4? Did I miss that, or did - except boxfx - nobody seen any difference?

Just curious.

And I would also like to know, if it is going to be changed again, or if that is the new setting we have to use? (Than it would be cool if these would be the new default settings. Even one click less can save a lot of time, with doing a lot of renderings during one year )

Thank you in advance!

Best regards

[Gpix]

Interestly enough,
that behaviour does not seem to occur, when a scene is created from scratch right away with minimum 2020.2.4 plugin Version.

Seems only to affect saved c4d-files where an previous version of the Octane plugin and the default render main settings was used and than you try to render that saved project with an updated version with default render main settings but with exact same camera settings in both versions...

So I assume, there was a change not only in the colormanagment behaviour of the render settings, but also in the camera imager?

[elsksa]

Since octane 2020.2.4 the setting: "Render settings > octane render > main > color space" has had sRGB and linear sRGB reversed. All my srgb renders are coming out pale and washed out with linear colour space and all my linear srgb renders are coming out as darker. This is only since updating from 2020.2 to 2020.2.4

This also seems affected by switching from premultiplied alphas + keep background and straight alphas + not keeping background

srgb.jpg

Hi, there are some misconception and incorrect terminology in this forum thread.

This page covers the basic understanding of what Linear means: https://www.elsksa.me/scientia/digital-imaging/linear-in-digital-imagery including the following TLDR:
• Linear is not a color space,
• A conformation from Linear to sRGB display referred will always perceptually appear "less dark/contrasted, more washed out" if I use simple non-technical wording.
• An exported EXR from Octane will (should in theory) always be exported "linearly" (without any display electro-optical-transfer-function (mistakenly known as "̶G̶a̶m̶m̶a̶") applied, such as one of the sRGB EOTFs, as there is not only one).

Therefore, there should not be any problem in regard to Octane (core) 2020 and 2021, which I am myself using. While it could be specific to Octane Cinema 4D, I would often bet for a PEBCAK in the (post) workflow.

I hope it clarified some confusion and helped.