Filmic sRGB in material textures broken/wrong calculated with overdriven values #103107

New Issue

Michael Klein · 2022-12-10T18:02:47+01:00

Michael Klein commented

2022-12-10 18:02:47 +01:00

System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3080 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98

Blender Version
Broken: version: 3.5.0 Alpha, branch: master, commit date: 2022-12-10 12:43, hash: fe30856d83
Broken: version: 3.4.0, branch: blender-v3.4-release, commit date: 2022-12-07 11:39, hash: 175bd38201
Worked: n.a.

Short description of error
Switching an sRGB JPEG texture sequence to Filmic sRGB seems not to work as intended. The colors will be transformed wrong.

Exact steps for others to reproduce the error
Create a material with an 8-bit sRGB texture and switch to Filmic sRGB. In the compositor, this works as expected.

In my example, the floor will cause a reddish reflection in the car paint shader and the rails reflect extremely. It looks like the color values are overdriven here. This is definitely wrong.

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3080 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98 **Blender Version** Broken: version: 3.5.0 Alpha, branch: master, commit date: 2022-12-10 12:43, hash: `fe30856d83` Broken: version: 3.4.0, branch: blender-v3.4-release, commit date: 2022-12-07 11:39, hash: `175bd38201` Worked: n.a. **Short description of error** Switching an sRGB JPEG texture sequence to Filmic sRGB seems not to work as intended. The colors will be transformed wrong. **Exact steps for others to reproduce the error** Create a material with an 8-bit sRGB texture and switch to Filmic sRGB. In the compositor, this works as expected. In my example, the floor will cause a reddish reflection in the car paint shader and the rails reflect extremely. It looks like the color values are overdriven here. This is definitely wrong. ![blender_MrZhW8G3lj.jpg](https://archive.blender.org/developer/F14050337/blender_MrZhW8G3lj.jpg) ![blender_undQ5FKLt7.jpg](https://archive.blender.org/developer/F14050336/blender_undQ5FKLt7.jpg)

Michael Klein commented

2022-12-10 18:02:47 +01:00

Added subscriber: @Renderbicks

Michael Klein changed title from ~~Filmic sRGB in material textures broken/wrong calculated?~~ to Filmic sRGB in material textures broken/wrong calculated (overridden values)

2022-12-10 18:04:54 +01:00

Michael Klein changed title from ~~Filmic sRGB in material textures broken/wrong calculated (overridden values)~~ to Filmic sRGB in material textures broken/wrong calculated with overdriven values

2022-12-10 18:05:40 +01:00

Michael Klein commented

2022-12-10 18:50:00 +01:00

Here's a simplified scene with the issue. You can see that the color transform in the compositor is correct while the result in the viewport by the shader shows a strange result. Again: It looks like color values are overdriven and behaves like an "emission".

221210_Blender_350_Bug_Filmic_sRGB.blend

Here's a simplified scene with the issue. You can see that the color transform in the compositor is correct while the result in the viewport by the shader shows a strange result. Again: It looks like color values are overdriven and behaves like an "emission". [221210_Blender_350_Bug_Filmic_sRGB.blend](https://archive.blender.org/developer/F14050455/221210_Blender_350_Bug_Filmic_sRGB.blend) ![221210_Blender_350_Bug_Filmic_sRGB.jpg](https://archive.blender.org/developer/F14050414/221210_Blender_350_Bug_Filmic_sRGB.jpg)

Michael Klein commented

2022-12-10 19:09:03 +01:00

Lowering the background light shows the suspicion that the color transformation is faulty here.

Lowering the background light shows the suspicion that the color transformation is faulty here. ![blender_kpdn7UXybH.png](https://archive.blender.org/developer/F14050484/blender_kpdn7UXybH.png)

Steffen Dünner commented

2022-12-11 17:32:52 +01:00

Added subscriber: @SteffenD

Steffen Dünner commented

2022-12-11 17:32:52 +01:00

I guess there's nothing wrong with the Color Management. If you set your image's input transform to "Filmic sRGB" and set your Exposure to something like -5...

... you'll see that the pixels close to 1.0 (white) in your original JPEG will be boosted to ~16.3 to show full white after Filmic is applied. Slight tints of color (in this case a slight tint of pink / purple) will also be boosted from very close to white to something very pink and purple. This is what happens on the rail that reflects in the car body:

The water in the back shows the same:

And look what all of a sudden happens in the completely blown out sky (which looks constant white):

Blocky compression artefacts in yellow and teal.

I guess the only thing you can do is to desaturate this texture to avoid the pink reflection in your car.

I guess there's nothing wrong with the Color Management. If you set your image's input transform to "Filmic sRGB" and set your Exposure to something like -5... ![image.png](https://archive.blender.org/developer/F14052467/image.png) ... you'll see that the pixels close to 1.0 (white) in your original JPEG will be boosted to ~16.3 to show full white after Filmic is applied. Slight tints of color (in this case a slight tint of pink / purple) will also be boosted from very close to white to something very pink and purple. This is what happens on the rail that reflects in the car body: ![image.png](https://archive.blender.org/developer/F14052487/image.png) The water in the back shows the same: ![image.png](https://archive.blender.org/developer/F14052491/image.png) And look what all of a sudden happens in the completely blown out sky (which looks constant white): ![image.png](https://archive.blender.org/developer/F14052493/image.png) Blocky compression artefacts in yellow and teal. I guess the only thing you can do is to desaturate this texture to avoid the pink reflection in your car.

Steffen Dünner commented

2022-12-11 17:54:01 +01:00

Just for fun I tried desaturating only the brightest highlights and saved the texture as an 8-bit PNG. Visually it is very very close to the original, but it renders without the annoying tint:

Left is the desaturated version, right the original.
And here's the desaturated texture I used:

Just for fun I tried desaturating only the brightest highlights and saved the texture as an 8-bit PNG. Visually it is very very close to the original, but it renders without the annoying tint: ![image.png](https://archive.blender.org/developer/F14052522/image.png) Left is the desaturated version, right the original. And here's the desaturated texture I used: ![CC0001.png](https://archive.blender.org/developer/F14052525/CC0001.png)

Brecht Van Lommel commented

2022-12-11 18:43:58 +01:00

Added subscriber: @brecht

Brecht Van Lommel commented

2022-12-11 18:43:58 +01:00

Changed status from 'Needs Triage' to: 'Archived'

Brecht Van Lommel closed this issue

2022-12-11 18:43:58 +01:00

Brecht Van Lommel commented

2022-12-11 18:43:58 +01:00

Don't use Filmic sRGB for base color textures, that's not its purpose and it will generate color values > 1. It's meant for emission or compositing.

Its purpose is explained in the release notes:

A new Filmic sRGB colorspace was added for images. This may be used for compositing background plates into a render that uses a Filmic view transform, without changing the look of the background plate. Using Filmic sRGB will convert 0..1 range colors into HDR colors in the scene linear color space. (2b80bfe2b8, 33f5e8f33f)

Don't use Filmic sRGB for base color textures, that's not its purpose and it will generate color values > 1. It's meant for emission or compositing. Its purpose is explained in the release notes: > A new Filmic sRGB colorspace was added for images. This may be used for compositing background plates into a render that uses a Filmic view transform, without changing the look of the background plate. Using Filmic sRGB will convert 0..1 range colors into HDR colors in the scene linear color space. (2b80bfe2b8, 33f5e8f33f)

Michael Klein commented

2022-12-11 19:16:36 +01:00

In #103107#1458681, @brecht wrote:
Don't use Filmic sRGB for base color textures, that's not its purpose and it will generate color values > 1. It's meant for emission or compositing.

Its purpose is explained in the release notes:

A new Filmic sRGB colorspace was added for images. This may be used for compositing background plates into a render that uses a Filmic view transform, without changing the look of the background plate. Using Filmic sRGB will convert 0..1 range colors into HDR colors in the scene linear color space. (2b80bfe2b8, 33f5e8f33f)

Thanks for the explanation. The idea to use the "corrected plate" was to keep the original colors of the "reflecting" backplate camera-projected because the HDRI alone is not correctly behaving in a camera movement. There is a way to "flatten" the lower part of the "sphere" to a flat ground for a better result but this distorts the HDRI map. I prefer the projection trick but have not tested the other method.

Overall a "constant material" in Blender would be very useful to render mattes for reflected objects or set the floor in my case to a "constant textured material" not being affected by the lighting but supporting the shadow catcher. In reality the floor is of course a "diffuse reflector" like every object but an emission material doesn't work with a shadow catcher. Integrating objects is still a tricky part. Especially if they are high reflective. Then I would get into trouble with the transition between the ground projection and the HDRI environment.

> In #103107#1458681, @brecht wrote: > Don't use Filmic sRGB for base color textures, that's not its purpose and it will generate color values > 1. It's meant for emission or compositing. > > Its purpose is explained in the release notes: >> A new Filmic sRGB colorspace was added for images. This may be used for compositing background plates into a render that uses a Filmic view transform, without changing the look of the background plate. Using Filmic sRGB will convert 0..1 range colors into HDR colors in the scene linear color space. (2b80bfe2b8, 33f5e8f33f) Thanks for the explanation. The idea to use the "corrected plate" was to keep the original colors of the "reflecting" backplate camera-projected because the HDRI alone is not correctly behaving in a camera movement. There is a way to "flatten" the lower part of the "sphere" to a flat ground for a better result but this distorts the HDRI map. I prefer the projection trick but have not tested the other method. Overall a "constant material" in Blender would be very useful to render mattes for reflected objects or set the floor in my case to a "constant textured material" not being affected by the lighting but supporting the shadow catcher. In reality the floor is of course a "diffuse reflector" like every object but an emission material doesn't work with a shadow catcher. Integrating objects is still a tricky part. Especially if they are high reflective. Then I would get into trouble with the transition between the ground projection and the HDRI environment.

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Filmic sRGB in material textures broken/wrong calculated with overdriven values #103107