Does anyone know where I can find an accurate detailed complilation of albedo vaules for a lot of materials?

I am currently doing some research on lighting and materials. I have found some charts but was wondering if there is a dedicated site for this in both srgb and linear?

Thanks

## Replies

http://wiki.polycount.com/wiki/PBR

Found this:

https://www.artstation.com/shinsoj/blog/Q9j6/albedo-chart

The color space conversions formula. I am not sure how they are calculated. I tried converting linear rgb of 0.27 from the picked color to srgb and I got around 11.33 for srgb. How do u get the r, g, b for srgb vaules from a Linear rgb?

I understand that albedo vaules for dielectric are a combination of both albedo and specular reflected light. So I presume albedo vaules is sort of a representation of the amount of light these surfaces reflect. Then what about the roughness of the surface? Does this involve the roughness of these surfaces that determine how much of the light is absorbed or reflected or albedo vaules have nothing to do with surface roughness at all?

From linear to srgb is power of 2.2.

To convert from 0-1 range to 0-255 range is by multiplying the value by 256.

From 0-255 to 0-1 range is a division by 256.

If its rgb values instead of a float, you need to apply these math on all 3 components separately.

Where Metalness is black, Albedo acts as the dielectric Diffuse color. Where Metalness is white, Albedo acts instead as the metallic Reflection color.

So, it's an optimization to store both Specular reflection and diffuse response, in one color texture. With the Metalness acting as a mask between the two different material types.

Roughness is a separate control entirely. Albedo has nothing to do with Roughness.

You might see something funky if the BRDF is not great at energy conservation... then full Roughness will decrease the brightness of the total light bounced off the surface, full Roughness making surfaces get darker.

This is physically incorrect though. The surface should be about the same brightness overall, whether it's zero Roughness or full Roughness.

Hope that makes sense. It's a bit weird to wrap my head around, but that's what I understand of the PBR talks and papers.

mutiplying 0.27 with 256 gives 69.12 which is close to the brightness vaule of the color picked in artstation post- 67%

why 256? Isn't it supposed to be 255?

How do u use the albedo chart tbh in ue4 or offline renderers? say Terracotta tile- 0.28. Convert 0.28 to srgb- 71.4, right?

So, that is the brightness vaule for whatever color u are going to use for terracota in srgb?

255/255 = 1

etc.

@Obscura I am tying to get what u wrote:

From linear to srgb- 0.27^2.2 ?

or 0.27 x 255 to convert to 0- 255 range, so where is power of 2.2 used?

Could u pls look at the equation in the artstation link

https://www.artstation.com/shinsoj/blog/Q9j6/albedo-chart

Is this correct?