Maniphest T70393

Filmic Affects Non-EXR file formats with wrong Gamma
Closed, ArchivedTO DO
Actions

Assigned To
None
Authored By
Fahad Hasan (cgvirus)
Sep 30 2019, 4:13 PM
Tags
  • BF Blender
Subscribers
Fahad Hasan (cgvirus)
Marcin Twarowski (Tvaroog)
Sam Brubaker (rocketman)

Description

System Information
Operating system: Linux-5.2.0-2-amd64-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: GeForce GTX 950/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.50

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
Worked: (optional)

Short description of error
Filmic Affects Non-EXR file formats (PNG,TIFF,JPG etc) with wrong Gamma conversion. Standard management gives correct gamma same as EXR. (examples attached)

Exact steps for others to reproduce the error

  1. Render a still with Filmic and save as PNG and as an EXR
  2. Render the same still with Standard Color Management as PNG
  3. Check any compositor like Natron, Nuke or Blender with (standard color management) to see the difference in gamma.

Example:

untitled Filmic.exr55 KBDownload

Related Objects

Event Timeline

Fahad Hasan (cgvirus) created this task.Sep 30 2019, 4:13 PM
ogierm added a subscriber: ogierm.Sep 30 2019, 8:51 PM
Marcin Twarowski (Tvaroog) added a subscriber: Marcin Twarowski (Tvaroog).Oct 1 2019, 9:42 AM

If you uncheck "save as render" .png will be saved with standard view transform.

ogierm removed a subscriber: ogierm.Oct 1 2019, 4:22 PM
Fahad Hasan (cgvirus) added a comment.Oct 1 2019, 4:49 PM

Interesting. It means only Linear Color Space supported formats should be delivered with Filmic and non-linear formats should be delivered with Standard automatically by Blender.
Seems like a TO DO.
https://developer.blender.org/T68926

Fahad Hasan (cgvirus) edited a custom field.Oct 1 2019, 4:50 PM
Sam Brubaker (rocketman) added a subscriber: Sam Brubaker (rocketman).Oct 2 2019, 7:11 AM

Color management can be tricky and misleading, but I don't believe this is a valid todo.

  • When saving to OpenEXR, Blender only uses the linear scene referred RGB data. It does NOT apply any transforms or color management settings, nor should it.
  • The color transforms for both Filmic and "Standard" are only applied to non-float image formats (like PNG), when "Save as Render" is enabled (which it is by default).
  • EXRs, when opened in an external application, may appear identical to PNGs or TIFFs saved with Standard color transform, but they are absolutely not the same! Other apps just come with their own "Standard" view transform when viewing EXRs; it is a more commonly supported color space than Filmic.
  • Linear is not a color space, nor are there to my knowledge any explicitly "linear" image formats.
  • The Filmic transform is not wrong, it's just different and not supported by default in most other apps.
Fahad Hasan (cgvirus) added a comment.Oct 2 2019, 2:35 PM

Thanks for the points @Sam Brubaker (rocketman) . Yes, I am understanding it now.
TO DO as in the task above, Blender has a broken system for color management for now. Specially the 2D viewer (for texture and compositing) and 3D viewer (for scene referred to display referred calculation). And then there is 8 Bit output limitation.
The task has pointed out all the points so I am archiving it hoping devs will come back to it in future.

Fahad Hasan (cgvirus) changed the task status from Unknown Status to Unknown Status.Oct 2 2019, 2:35 PM