compositing elements with affect all channels

[Guest]

I have a transparent object that I wish to composite together however when I use affect all channels for the transparent material the resulting comp is over bright. If I choose not to affect channels the resulting comp is the correct brightness. Is it not possible to composite elements that have affect all channels enabled on a transparent material? Using 32-bit EXR files.

It may be because when I linear dodge (add) an element that has transparency it is forcing it to become too bright? Any help on this would be great.

[Guest]

Within the Vray manual it states: -All channels - all channels and render elements will be affected by the transperency of the material. So when composited together to create a beauty pass, the result is overbright :/

[Guest]

Never mind I got the answer. With affect all channels the refraction layer is effectively built in to the other layers so there is no need for it to be included in the comp. This is what causes the resulting comp to be too bright.

[rjohnson33]

Can I ask if this solution is still working out for you in your compositions?

I'm finding the same issues as you originally stated (overbright reflections in composite compared to beauty pass) and I have affect all channels selected for transparent materials
but if I omit the refraction element from the comp as you suggest then I lose the information behind any refractive materials - as in the comp (GI + Lighting + Reflection + Specular) doesn't equal beauty pass.

GI + Lighting + Reflection + Refraction + Specular, still gets me closer to the beauty pass but still with brighter reflections on or around (light that has passed through) refractive materials.
I have no SSS2 materials by the way (I understand these need to be added as a separate element if used)
Interestingly the difference in the overbright reflections compared to beauty pass decreases (but doesn't dissappear entirely) if clamp output and sub-pixel mapping are turned off.
All other parameters here are set up in a linear fashion and the compositing is being done in after effects