Wrong behaviour with "RGB to Intensity" in Image textures. Wrong color #48002

New Issue

msalv · 2016-03-30T14:24:44+02:00

msalv commented

2016-03-30 14:24:44 +02:00

System Information
Debian Jessie 8.2 64-bit, and Windows 10 64bit
Intel i5-2500
GeForce GTX 970

Blender Version
Broken: 2.76, 2.77
Worked: (optional)

Short description of error

Using "RGB to Intensity" with an Image texture gives the wrong color. The proof is that the proper color is displayed when using "RGB to Intensity" with a procedural texture, while with an Image texture the color is darker.

Exact steps for others to reproduce the error
Just open the file attached bugreport.blend and check the example in both render and glsl/texture view. All materials displayed have the exact same colors assigned. You can check that the procedural example has the same settings as the image texture example.

A workaround I found is either using float precision image textures, or changing the color space of the image texture to linear, raw, or non-color. However doing this makes no sense, since the image is black and white and its being used to mask a color I selected in the color picker of the "RGB to Intensity" section. This color should not become darker because of the colorspace of the texture being sRGB. Another problem with that workaround is that it doesnt work in glsl view.

For the GLSL view, a workaround is to use nodes. There is also an example of that in the file attached. Again, the colors are the same. And this is further proof that the colorspace of the texture should not make that green color darker, because this node approach still works well when changing the color space of the texture mask.

I went back to older versions to test it, and it never worked properly from 2.5 on. Back in 2.49 there was no color space, so there all 3 colors look the same. The same effect can be done in 2.77 by changing the scene display device to "none". But going back to sRGB and that one in the middle stays dark. It seems the color in "rgb to intensity" remains without gamma correction if an image texture is used.

**System Information** Debian Jessie 8.2 64-bit, and Windows 10 64bit Intel i5-2500 GeForce GTX 970 **Blender Version** Broken: 2.76, 2.77 Worked: (optional) **Short description of error** Using "RGB to Intensity" with an Image texture gives the wrong color. ![desktop.png](https://archive.blender.org/developer/F299551/desktop.png) The proof is that the proper color is displayed when using "RGB to Intensity" with a procedural texture, while with an Image texture the color is darker. **Exact steps for others to reproduce the error** Just open the file attached [bugreport.blend](https://archive.blender.org/developer/F299550/bugreport.blend) and check the example in both render and glsl/texture view. All materials displayed have the exact same colors assigned. You can check that the procedural example has the same settings as the image texture example. A workaround I found is either using float precision image textures, or changing the color space of the image texture to linear, raw, or non-color. However doing this makes no sense, since the image is black and white and its being used to mask a color I selected in the color picker of the "RGB to Intensity" section. This color should not become darker because of the colorspace of the texture being sRGB. Another problem with that workaround is that it doesnt work in glsl view. For the GLSL view, a workaround is to use nodes. There is also an example of that in the file attached. Again, the colors are the same. And this is further proof that the colorspace of the texture should not make that green color darker, because this node approach still works well when changing the color space of the texture mask. I went back to older versions to test it, and it never worked properly from 2.5 on. Back in 2.49 there was no color space, so there all 3 colors look the same. The same effect can be done in 2.77 by changing the scene display device to "none". But going back to sRGB and that one in the middle stays dark. It seems the color in "rgb to intensity" remains without gamma correction if an image texture is used.

msalv commented

2016-03-30 14:24:44 +02:00

Changed status to: 'Open'

msalv commented

2016-03-30 14:24:44 +02:00

Added subscriber: @moisessalvador

Bastien Montagne commented

2016-04-01 16:00:47 +02:00

Added subscribers: @Sergey, @mont29

Sergey Sharybin was assigned by Bastien Montagne

2016-04-01 16:00:47 +02:00

Bastien Montagne commented

2016-04-01 16:00:47 +02:00

That’s colors space issue, setting the image's colors space to Linear eg fixes it. Not at all an expert in this are, so will let @Sergey check whether behavior here is expected/correct, or if we are missing some conversion somewhere…

msalv commented

2016-04-01 16:05:44 +02:00

No problem. I think I provided enough evidence and explanations on why this is inconsistent and should be considered a bug, and I hope you take it into consideration.

blender-admin commented

2016-04-04 11:30:35 +02:00

This issue was referenced by 2f08d5f761

This issue was referenced by 2f08d5f761e6941e11a712d0cbee2f7bd65e4c91

Sergey Sharybin commented

2016-04-04 11:30:43 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2016-04-04 11:30:43 +02:00

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Wrong behaviour with "RGB to Intensity" in Image textures. Wrong color #48002