### Author Topic: Dielectric Specular value when converted from metal-rough  (Read 2362 times)

#### mario.baldi

Hi there, I am writing this one just out of curiosity.

I know that both Designer and Painter, when converting a dielectric material from a metal/rough texture set to spec/gloss (i.e. when the metal map is black), assign a flat gray color to the specular map.

Now, from what I know this gray color should represent a fixed valued of 0.04 (in a range from 0 to 1 in a linear gamma).

What I noticed is that Substance Designer assign a sRGB color of 59 to the specular map, but I can't understand this value.

Theoretically 4% of 255 (rgb range) is 10.2, which in sRGB becomes 10.2*2.2 = 22.44

So my genuine question is, what am I doing wrong?
Thank you

#### Nicolas Wirrmann

Hi,

The conversion from linear to sRGB is ^0.4545 (or ^1/2.2). Not *2.2.
0.04 ^ 0.4545 = 0.2315
0.2315 * 255 = 59

Cheers,
Nicolas
Product Manager - Allegorithmic

#### mario.baldi

Thank you Nicholas, I always have big problems understanding linear and sRGB gamma conversion