Lol
Actually, that was the first time, I didn't want to (too tired) but when you ask me for, that "kind" ^^
SOOOOO
A B and C are for Indigo to know, how to interpret the textures.
Standard usually is
A 0 B 1 C 0
This is translated as "the darkest colour is pure black, the brightest colour is pure white" - B stands for the brightest colour and C for the darkest.
A is a value, you'll want to change VERY seldom. It strongly increases the contrast... Which also is done by the difference of B and C...
For albedo maps (colour maps) the standard settings should be just fine.
Maybe, you'll want to give slightly higher C, if your texture has (quite big) black parts, as pure black might look odd, especially in combination with reinhard tonemapping.
For Blend maps, the Standard settings are recommended.
For Exponent maps, B and C give the actual exponent. I wonder, how they are defined... If the values are tweaking the exponent 1:1, the default value will be quite useless...
In that case (and I don't know, IF it is the case), you'll need to set your B to the maximum Exponent you want to use (Exponent infinite = fully specular) and your C to the minimum Exponent, you want to use. (Exponent of 0 = fully Diffuse)
For Bumps, your B value sets your bumpiness... As a B of 1 gives extremely deep bumps, already, I guess that it's translated in meters. So, if you roughly know how deep the bumpmap actually is, translate that depth to meters and use it as your B
- Here, pure blacks might also look strange, so you'll want to slightly increase your C, too
Ok.... Now to the A value:
The three values translate the texture's pixels in Ax²+Bx+C=interpreted Value (Where x is the R G and B values of the image)
So, if you change all your Bs to 0 and therefore put the same values in A, you actually translate the image to have a quadratic gradient, resulting in sharper appearance... Overally, it might not be the easiest value to control, but under circumstances, especially where you need contrast, it could be very useful
You might want to try it on bump- and exponent maps... albedo and especially blend maps most likely come out weird.
One more thing: Indigo uses normalized colours... So, if you want to increase the darkest colour of your image by 1 of 255 possible steps, you need to add 0,00392 to the C-value.
The conversion is simple: If you want to convert any value from palette RGB to Normalized RGB, you simply need to divide your value by 255.
The other way round works via multiplying 255, obviously.
I hope, this is helpful.
And I hope, a(n if needed) corrected and maybe illustrated version of this comes into the manual...
Which I hope gets updated soon.
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