There’s a odd behavior in the sss radius in cycles that I don’t get in other render engines such as iray. Below an example where I get an odd sss tint with christensen burley, while it works fine with random walk.
Also another example where the scattering seems to vary too much with the tint. A pale sss tint almost blurs away all the facial features. Again this is much more visible in chris than in random walk. Again I don’t get this behavior in iray where the scattering mostly depends on the sss factor, not on the tint.
Please let me know what you think about it so I may open a support ticket at blender dev. Or if this is the intended behavior any explanation would be fine to have thanks. Scene included.
Im not 100% sure about this theorie. Colors differ in wavelength and due to that some travel deeper than others. But im not sure if Cycles also takes this into account. I dont think Cycles is physical accurate in this part.
Best way to test SSS is do render tests with different values. ALso note down the values or store them so you understand your images better.
Im not a cycles user, but should that purple input also receive a purple node?
Yiou need to put that color in the sub surface color. This is how Radius is explained
Which does sound like the wavelenght i just explained
Radius
Average distance that light scatters below the surface.
Higher radius gives a softer appearance, as light bleeds into shadows and through the object.
The scattering distance is specified separately for the RGB channels, to render materials such as skin where red light scatters deeper.
The X, Y and Z values are mapped to the R, G and B values, respectively.
