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Clay render default value

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Clay render default value

Post Wed Mar 16, 2016 4:15 pm

Hi all,

As Samo explains on his excellent workflow:

http://www.yafaray.org/node/667

I propose that Render clay default colour changes from #BCBCBC to #808080.

Thanks
surena
 
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Re: Clay render default value

Post Wed Mar 16, 2016 5:36 pm

Hello,

The Clay default color was redefined in the last review of the YafaRay Color Spaces system, where I implemented a more correct sRGB color management.

Currently the Clay default color is exactly middle gray in the Linear color space (0.5,0.5,0.5).

However, Blender color picker shows values in a slightly confusing way:
* Floating point components of the color are shown in linear color space (0.5,0.5,0.5)
* Hex color components are shown already converted to the selected Color Space in Blender. For example, if you select color space sRGB, you will see it's 0.5,0.5,0.5 but the hex value is BCBCBC. If you select color space "none" you will see the same floating point values 0.5,0.5,0.5 and the hex value 808080

So, the current implementation of color spaces and clay default color is supposed to be mathematically correct to be 0.5 in the linear color space, which is the space where all rendering calculations take place.

Of course, I could be wrong but samo and me worked on this for quite some time and agreed most of those changes and definitions.

Best regards!
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David Bluecame
 
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Re: Clay render default value

Post Wed Mar 16, 2016 8:01 pm

But at the end, we work with gamma corrected textures, and the render we get is also gamma corrected. So finally the light perception is another. If I render with clay I obtain a render where this grey corresponds almost to the white color when is gamma corrected. IMO
surena
 
Posts: 94
Joined: Sat Apr 26, 2014 6:37 am
Location: Spain

Re: Clay render default value

Post Thu Mar 17, 2016 4:02 am

Hello,

I've been looking at this and you are absolutely right, my mistake. I've totally misunderstood the Middle Gray. As you say, it should not be 50% in linear space, but 50% in sRGB converted space (which is 21.40% in linear space acording to https://en.wikipedia.org/wiki/Middle_gray )

I will change the default Clay value to 0.216,0.216,0.216 in linear space (which corresponds to sRGB 50% reflectance and 808080 hex)

This change will be available in the next YafaRay-E version. In the mean time you can change the clay color using the clay color picker to set this value manually.

Thank you for your feedback again! :-)
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David Bluecame
 
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