Add View Transform space to inactive_colorspaces Causes extra transform when saving 16 bit PNG #103470

New Issue

Zijun Zhou · 2022-12-26T01:34:14+01:00

Zijun Zhou commented

2022-12-26 01:34:14 +01:00

System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3050 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98

Blender Version
Broken: version: 3.5.0 Alpha, branch: master, commit date: 2022-12-24 00:06, hash: 4701421dbe
Worked: none

Short description of error
OCIOv2 has an inactive_colorspaces feature, we can basically replace our legacy doing of family: display with this new feature. But there is one strange bug, when you add a view transform space as inactive, it looks normal in Blender, but when you save a 16 bit PNG, the PNG has additional power function applied. Don't want to say it that surely but I think it's a 2.2 OETF curve, something hardcoded?

Exact steps for others to reproduce the error

Open Blender's OCIO config with a text editor.
Remove the False Color space's display family.
Add a line under the displays, that says inactive_colorspaces: [False Color]
Like this:
Save the edit, open Blender, it works fine in Blender itself, check texture colorspace list, no False Color in the list.
Load an EXR in Image Editor and save 16 bit PNG, see how the saved PNG is brightened with an additional power curve applied.

Sweep EXR for example:

Save as 16 bit PNG:

False Color in Blender:

Saved PNG:

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3050 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98 **Blender Version** Broken: version: 3.5.0 Alpha, branch: master, commit date: 2022-12-24 00:06, hash: `4701421dbe` Worked: none **Short description of error** OCIOv2 has an `inactive_colorspaces` feature, we can basically replace our legacy doing of `family: display` with this new feature. But there is one strange bug, when you add a view transform space as inactive, it looks normal in Blender, but when you save a 16 bit PNG, the PNG has additional power function applied. Don't want to say it that surely but I think it's a 2.2 OETF curve, something hardcoded? **Exact steps for others to reproduce the error** 1. Open Blender's OCIO config with a text editor. 2. Remove the `False Color` space's `display` family. ![image.png](https://archive.blender.org/developer/F14143820/image.png) 3. Add a line under the displays, that says `inactive_colorspaces: [False Color]` Like this: ![image.png](https://archive.blender.org/developer/F14143823/image.png) 4. Save the edit, open Blender, it works fine in Blender itself, check texture colorspace list, no False Color in the list. ![image.png](https://archive.blender.org/developer/F14143826/image.png) 5. Load an EXR in Image Editor and save 16 bit PNG, see how the saved PNG is brightened with an additional power curve applied. Sweep EXR for example: ![Sweep_sRGB_Linear_Full.exr](https://archive.blender.org/developer/F14143829/Sweep_sRGB_Linear_Full.exr) Save as 16 bit PNG: ![image.png](https://archive.blender.org/developer/F14143848/image.png) False Color in Blender: ![image.png](https://archive.blender.org/developer/F14092749/image.png) Saved PNG: ![Sweep_sRGB_Linear_Full.png](https://archive.blender.org/developer/F14092753/Sweep_sRGB_Linear_Full.png)

Zijun Zhou commented

2022-12-26 01:34:14 +01:00

Added subscriber: @Eary