Reduce Black crush / white crush in vray 6

[malan9999]

I'm liking the additional tonemapping controls in the VFB, but find it hard to find something as effective as the Highlight / Shadows command in Photoshop. I've posted an example of where I wanted the render to go using the Shadow / Highlight command in photoshop.
Is there a way to get to this using the existing tools? I've tried contrast / highlight compression but they're altering a lot more than I want to.

Would be a great addition to the VFB to have this functionality added.

[vladimir_krastev]

Hi could you send us the exr/vrimg file to test? Which controls have you added in VFB (screengrab of the layers or a layer pre-set will be great to have)?

[malan9999]

Hi,
Here's the link to the files.

https://we.tl/t-Bdrojvu9BP

thanks

[^Lele^]

Thanks for the chance to have a play with great content!
I have turned off most of the stuff that was there, and reused what i thought i'd need: an exposure and a Hable tonemap (you had both.).
I also slightly raised saturation.
The match with your PS reference seems close enough to me, but you'll be the judge of that.
You will want to play with the Hable tonemap controls, in general, to roll off highlights and to expand or crush the blacks.
I used indicative (not exact, in other words) values, so feel free to tweak them to your heart's content.

p.s.: some of your blacks are very marginal (the mud guard of the car, f.e.) for intensity, sitting at 0.005f or so. If you plan on doing post, you'll want to either lower noise threshold, or brighten them slightly, so that you won't incur in noise issues when pulling them up later.

[malan9999]

Thanks Lele. The exercise was about getting a punchy image while not crushing the blacks and whites, but I think yours it a bit softer less contrasty version.
I think the ideal solution is to have a new function similar to the shadow / highlight tool within the VFB that you apply at the end of the chain to rein in the values at the extreme end of the luminance range.

Either that, or adding a luminance range / mask option on all the existing channels so you can choose to effect only the midrange luminance areas for example.

I'm thinking of generating a LUT from photoshop as a temporary solution. Will post an update later.

[^Lele^]

Thanks Lele. The exercise was about getting a punchy image while not crushing the blacks and whites, but I think yours it a bit softer less contrasty version.
I think the ideal solution is to have a new function similar to the shadow / highlight tool within the VFB that you apply at the end of the chain to rein in the values at the extreme end of the luminance range.

Either that, or adding a luminance range / mask option on all the existing channels so you can choose to effect only the midrange luminance areas for example.

I'm thinking of generating a LUT from photoshop as a temporary solution. Will post an update later.

As mentioned, try and *slightly* change the values for the hable tonemap (f.e. lower linear angle), and you'll get the image exactly where you'll want it. (p.s. the EXR you attached is exceptionally crunched in the blacks. is that the target you want to aim for?)
You had a stack of a dozen CCs in your original image, often fighting with each other.
The math to do what you want is already there, and in a few places too, you just need to look at the drawn curve and do a colorpick or two to adjust the values.
LUTs won't work nearly as well with full FP material, and you're likely to get clipping.

[malan9999]

Here's the updated version with custom LUTs used. I created 2 versions with differing methods and they improve a bit on the black crush / white crush.

[malan9999]

If anyone's interested I can upload the LUTs, but don't have any permanent file-hosting so it'll just be for a week until it expires.

[piotrus3333]

the issue here is something else. your raw render does not look right, its too flat as in not enough dynamic range (materials and lighting, mostly lighting). tone mapping is not the right way to go as there is nothing to tone map. no properly hot highlights. apply just curves and you get all the control you have in photoshop.
this is more along what you should expect raw to look like:
https://we.tl/t-jFEfy7wYeW

[malan9999]

I've loaded up the 32 bit exr with no adjustments and it's got a pretty wide dynamic range. Using an exposure adjustment shows information from -8 to +7 (stops I think). In any case all materials and lighting in the scene came direct from Chaos Cosmos with standard everything.
With regard to using curves in the VFB, it's not a great idea to do too much in RGB as will mess up saturation as well. You can see this effect in photoshop. The only way to use curves without messing up colour information is to convert to LAB mode and apply curves to the Luminance channel (L)

[malan9999]

Here's the link to the raw exr.
https://we.tl/t-sURrxKyHTw

[piotrus3333]

my bad.
I thought "Bike shot.exr" was the raw.

but anyway you control that with curves. highlight compression =0 and curves.
if you need to control hue/sat separately do one curve with blending mode value and second (or more) one with color, hue or sat.

there no better tool to do what you need. just curves.

[malan9999]

Ok thanks for the info. Still on Vray next so not that familiar with all the extra features. Will look into that.