rancax

cool man thanks! that was exactly what I was needed!
 
This was my problem > Because of stupid adobe's decisions or laziness or whatever you gonna call it - 32 bit exr's when imported, only about 40 percent of functionality works in PS, BUT no hassle, all render passes just set linear dodge/add and good to go ( this is simple ''BACK TO BEAUTY'' ) workflow... but when it comes to 8 BIT, OR 16 it's different blendings on different layers!!! And since I JUST COULD NOT FIND BLENDING MODES FOR THOSE RENDER PASSES, then you'll have to switch it to 16 bit and literally have to guess visually > which is not ''mathematically'' so to speak correct...
 
so in order to keep linear dodge/add blending modes within 16 bit mode ( if you set linear dodge/add on 32 bit and switch to 16 bit everything got messed up ) you'll have to make a profile which is essentially sRGB just insted of 2.2 gamma you type 1.0 save it, and temporarily it's ok, you switch to 16 bit and blend modes stay but there comes a BIG PROBLEM when you want to export as 8 bit-png, or jpg ( low dynamic range format ) renders got dark! very dark, like burned! because of that gamma conversion I guess... and it stays wheter you save foto with icc profile embeded or without or switch it to sRGB and do exactly same with or without.... and that is problem! 
And recreating a ''ADVANCED BACK TO BEAUTY'' is same, but because of advanced passes final result is not quite as rgb color render! Hell, i dont even know if is possible to recreate it in ''ADVANCED BACK TO BEAUTY'' and here is why ( I asked on chao's group forum and their member - Dans has helped me about formula regarding workflows on their's user manual but I'm quoting a different post about this problem ) so : >>>>
 
>>>> ''Originally posted by Richard7666 View Post
Is this doable, or is it impossible by definition?
Reason being, I currently work in Photoshop in 16bit, as I can still get good control of exposure etc AND still use things like the magic wand and various other tools that don't work in 32bit. Currently, I only use a beauty pass.
However, I'd like to start comping my passes separately, so I can edit my lighting pass individually and so on. 
Is there a way to comp 16bit passes back-to-beauty so I can still use all Photoshop's tools? Yes, you can. Let me explain:

The main problem with render elements (reflection, refraction...) is that they need to be composed in linear space. If you take a high dynamic range image like a 32-bit PSD or EXR file this will always be linear (so no gamma correction baked in). If you display such an image it will be gamma corrected automatically - just for display purposes (like the sRGB button in the V-ray Framebuffer). After Effects, Nuke etc. can do that, Photoshop does that too for 32-bit PSD images.

Your typical 8-bit or 16-bit PNG/TIFF/JPG saved by 3ds max already has gamma correction applied to it (Output Gamma 2.2 is the default). Your image editor or compositing software does not need to do anything special to display the image for you (ignoring color management here). But to combine several render elements these calculations need to be done in linear space - otherwise everything will not match your beauty pass (too bright). Compositing software like After Effects can do this (by internally converting into linear space when combining layers) but Photoshop does not do this (it has always been like that to make it fast). 

The trick is to save your 16-bit images without gamma correction and calculations will be correct in Photoshop. You just lack a way now to get the image to display correctly by applying gamma correction (like that sRGB button in the V-Ray Framebuffer). You will find the Exposure Adjustment layer in Photoshop has a Gamma correction option - but it does not match 3ds max.

The just released psd-manager version 4 can automatically save render elements in linear space and add a special constructed adjustment layer on top that matches 3ds max gamma correction. You just need to add your render elements to your 3ds max scene - the blending modes are assigned automatically. Have a look at the Trial version - it should help you do some tests. (Note: I'm the developer) You can also save a 32-bit PSD and compare. 
If you do standard back-to beauty compositing like outlined in the V-Ray documentation this will work in 16-bit PSDs. In simple terms if you just combine any of these: VRayLighting + VRayGlobalIllumination + VRayReflection + VRayRefraction + VRaySpecular + VRaySSS2 + VRaySelfIlumination + VRayCaustics + VRayAtmosphere using the Linear Dodge blending mode then you will be fine.

If you need to do Advanced Back to Beauty Compositing version then things get problematic only in areas where render elements have clipped values (so would have values above 1.0 in an HDR image). This problem has nothing to do with Photoshop itself - simply a low dynamic range limitation. '' <<<<<
 
So as he said :''But to combine several render elements these calculations need to be done in linear space - otherwise everything will not match your beauty pass (too bright) '' and I think he is right because I came across similar problem, but when you switch even your 32 bit exr's to 16 bit's ( half-float ) BUM! > Messed up and linear dodge formula doesn't work!!!! 
 
So in a way they made it impossible to do any kind of post production in damn PS.... It's like I'm buying a car to drive it in alaska but without winter tyres?!?!?!? I mean WTF... ( sorry for language )  
And yes Nuke or Fusion are different stories > they work with 32 bit exr's, even have native 32 bit depth of field with z-depth but that is not important > They dont have brushes and workspace if I want let say to paint on some passes or to utilize brushes, erasers, stamp tools etc....
I mean com'on it 21st century, how in the HELL DID THEY ALL GOT IT TO BE SO DAMN DIFFICULT AND HAND BANGING???? COULD NOT JUST ALL MAJOR BRANDS AND PROGRAMERS FORM, AND CGI HOTSHOTS sit together and work those problems out??? just to make universal workflow so to speak...... I'm not saying just guys from adobe, but chaos group as well and other major players... 
I mean it's really frustrating!!!! If I have to be a magican to know every god damn thing then to hell with it > what is then the point to express visually and artistically if I'm burried with tons and tons and tons of technicalities?!?!?! Maybe I'm going here with some philosophy but I think that is what a really good and beutiful design shoud be > to be easy to use, and simple! pure simplicity! 
 
And then I saw Affinity and it's beauty to import 32 bit passes and not to be limited as PS but to have full freedom to paint, effect, and other stuff which stupid PS doesn't have!!!!
keep on going guys, you're on right way just boost it to max!!!!
and thanks men for your answer, really appreciate it!
I hope i did not choke you guys for being this sufficient but just some thing, and supidity is driving me crazy...
Again did not meant anything wrong just a critic and personal views...
cheers