I will pick an example. I will create a thin glass polygon (one-sided, not a slab) which is at a 45 degree angle to the camera. I will place a color source behind it of a known color, as well as beside it, also of a known, but totally different color, and we shall see what the fresnel_blend gives us.

For the glass material, I will choose an IOR of 1.5.

For the color behind the glass, I will make a simple self-lit surface with RGB 128, 0, 0. (screen color space)

For the color beside the glass, I will make a simple self-lit surface with RGB 0, 0, 128. (Again, screen color space)

I will use the Orthographic camera so that all points on the slab will have an angle of incidence of 45 degrees.

According to this Fresnel calculator:

http://www.calctool.org/CALC/phys/optics/reflec_refrac

the amount of reflection for parallel and perpendicular polarized light are given and if we average them we get (9.20134% + 0.846646%) / 2 = 5.023993. This says I should see about 5% of the blue and about 95% of the red.

 

Given that the color components at 128, converted to linear space, is an intensity of 0.21951971807, I would expect that my red (refraction component) should be

(((1 - .05023993) * 0.21951971807) ** (1/2.2)) * 255 = 125

and that my blue (reflection component) should be

((.05023993 * 0.21951971807) ** (1/2.2)) * 255 = 32.86 (will it round up to 33?)

 

I have not yet tried the experiment. I'm honestly just telling the math up front. Assuming I did not make a mistake (which I may have) the resulting color of the glass will be RGB 125, 0, 32 (or 33).

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)