RGB values wrong calculated/displayed (ignoring Color Management) #71586

New Issue

Michael Klein · 2019-11-14T21:40:24+01:00

Michael Klein commented

2019-11-14 21:40:24 +01:00

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 1060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.20

Blender Version
Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-13 16:25, hash: 9bd0d8b550
Worked: (optional)

Short description of error
The RGB values will be displayed wrong. HSV and HEX are correct. The resulting color is correct.
The wrong decimal numbers seem to be a result by not considering the Color Management.

Exact steps for others to reproduce the error

Add RGB-node in compositor
Use Color example: 678F8F
Results

BLENDER

R: 0.136
G: 0.275
B: 0.275

RGB is wrong.

H: 0.500 (180°)
S: 0.280
V: 0.561

HSV is correct.
Output color on screen is correct.

Correct result in Maya:
R: 0.404
G: 0.561
B: 0.561

Correc result in Photoshop:
H: 180°
S: 28
B: 56

R: 103
G: 143
B: 143

In the attached picture you'll from left to right:
Blender Colors - Maya Colors (Color Management ON) - Maya Colors (Color Management OFF)

**System Information** Operating system: Windows-10-10.0.18362 64 Bits Graphics card: GeForce GTX 1060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.20 **Blender Version** Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-13 16:25, hash: `9bd0d8b550` Worked: (optional) **Short description of error** The RGB values will be displayed wrong. HSV and HEX are correct. The resulting color is correct. The wrong decimal numbers seem to be a result by not considering the Color Management. **Exact steps for others to reproduce the error** - Add RGB-node in compositor - Use Color example: 678F8F - Results BLENDER R: 0.136 G: 0.275 B: 0.275 RGB is wrong. H: 0.500 (180°) S: 0.280 V: 0.561 HSV is correct. Output color on screen is correct. Correct result in Maya: R: 0.404 G: 0.561 B: 0.561 Correc result in Photoshop: H: 180° S: 28 B: 56 R: 103 G: 143 B: 143 In the attached picture you'll from left to right: Blender Colors - Maya Colors (Color Management ON) - Maya Colors (Color Management OFF) ![191114_Blender_281_RGB_Wrong.jpg](https://archive.blender.org/developer/F8080198/191114_Blender_281_RGB_Wrong.jpg)

Michael Klein commented

2019-11-14 21:40:24 +01:00

Added subscriber: @Renderbicks

Michael Klein changed title from ~~RGB values wrong calculated (ignoring Color Management)~~ to RGB values wrong calculated/displayed (ignoring Color Management)

2019-11-14 21:43:30 +01:00

Steffen Dünner commented

2019-11-15 12:21:52 +01:00

Added subscriber: @SteffenD

Bent Hillerkus commented

2019-11-15 23:35:34 +01:00

Added subscriber: @bent

Germano Cavalcante commented

2019-11-20 23:21:11 +01:00

Added subscribers: @brecht, @mano-wii

Germano Cavalcante commented

2019-11-20 23:21:11 +01:00

It seems that there really is an inconsistency between the other applications and Blender.
I used this site to check the values: https://www.rgbtohex.net/hextorgb/

Looking at the code, I found that the rgb value changes in this line:
https://developer.blender.org/diffusion/B/browse/master/source/blender/editors/interface/interface_region_color_picker.c$307

@brecht, you have worked in this area before (a7b3d580), do you know why this happens?

It seems that there really is an inconsistency between the other applications and Blender. I used this site to check the values: https://www.rgbtohex.net/hextorgb/ Looking at the code, I found that the rgb value changes in this line: https://developer.blender.org/diffusion/B/browse/master/source/blender/editors/interface/interface_region_color_picker.c$307 @brecht, you have worked in this area before (a7b3d580), do you know why this happens?

Brecht Van Lommel commented

2019-11-20 23:34:56 +01:00

Changed status from 'Open' to: 'Archived'

Brecht Van Lommel closed this issue

2019-11-20 23:34:56 +01:00

Brecht Van Lommel self-assigned this 2019-11-20 23:34:56 +01:00

Brecht Van Lommel commented

2019-11-20 23:34:56 +01:00

By design, hex and HSV are sRGB, and RGB is scene linear.
https://docs.blender.org/manual/en/dev/interface/controls/templates/color_picker.html

By design, hex and HSV are sRGB, and RGB is scene linear. https://docs.blender.org/manual/en/dev/interface/controls/templates/color_picker.html

Michael Klein commented

2019-11-21 00:47:05 +01:00

In #71586#813990, @brecht wrote:
By design, hex and HSV are sRGB, and RGB is scene linear.
https://docs.blender.org/manual/en/dev/interface/controls/templates/color_picker.html

I assume RGB should also be sRGB and maybe adding a button to turn linear on/off. Otherwise it's totally confusing because the general RGB sliders of all programs are all using sRGB values. It doesn't make sense that V 0.5 is not RGB 0.5 0.5 0.5.

> In #71586#813990, @brecht wrote: > By design, hex and HSV are sRGB, and RGB is scene linear. > https://docs.blender.org/manual/en/dev/interface/controls/templates/color_picker.html I assume RGB should also be sRGB and maybe adding a button to turn linear on/off. Otherwise it's totally confusing because the general RGB sliders of all programs are all using sRGB values. It doesn't make sense that V 0.5 is not RGB 0.5 0.5 0.5.

Michael Klein commented

2019-11-21 16:22:31 +01:00

I found out that Maya is using linear for RGB and HSV. Maya just shows it different. Attached you see the screenshot of the sliders with linear Color Management on and off. In Blender you'll see it at the vertical greyscale bar.

I found out that Maya is using linear for RGB and HSV. Maya just shows it different. Attached you see the screenshot of the sliders with linear Color Management on and off. In Blender you'll see it at the vertical greyscale bar. ![191121_Maya_Linear_RGB.jpg](https://archive.blender.org/developer/F8151763/191121_Maya_Linear_RGB.jpg)

Michael Klein commented

2019-11-21 16:52:51 +01:00

To clarify:
Maya is generally set to linear for RGB and HSV. Maya is not supporting HEX.

I can't copy RGB/HSV values from PSD to Maya. I can preview the PSD sRGB color when I turn Color Management off but I still have the linear result. A workaround is to split the screen and use a color picker in Maya and pick the PSD color.

But I can copy HEX from PSD to Blender. The linear RGB numbers can be copied correctly to Maya.

So the Blender method seems to be good/better. Color Management is always confusing.

To clarify: Maya is generally set to linear for RGB and HSV. Maya is not supporting HEX. I can't copy RGB/HSV values from PSD to Maya. I can preview the PSD sRGB color when I turn Color Management off but I still have the linear result. A workaround is to split the screen and use a color picker in Maya and pick the PSD color. But I can copy HEX from PSD to Blender. The linear RGB numbers can be copied correctly to Maya. So the Blender method seems to be good/better. Color Management is always confusing.

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RGB values wrong calculated/displayed (ignoring Color Management) #71586