Chaos Corona Forum

General Category => General CG Discussion => Topic started by: Gewiz90 on 2017-06-22, 04:15:39

Title: LUT
Post by: Gewiz90 on 2017-06-22, 04:15:39
Hey can someone help me? I'm looking for a good LUT for photoshop cc to make my interior scenes more realistic? Tx
Title: Re: LUT
Post by: maru on 2017-06-22, 11:15:47
If you download and install Corona Renderer (https://corona-renderer.com/download), you will end up with over 80 free LUTs in C:\Program Files\Corona\lut :)
Title: Re: LUT
Post by: romullus on 2017-06-22, 12:18:32
Yeah, but those are not really usable in photoshop AFAIK.
Title: Re: LUT
Post by: maru on 2017-06-22, 17:57:42
I have little knowledge about LUTs, but why is that?
Title: Re: LUT
Post by: romullus on 2017-06-22, 19:30:39
So do i. I'm basing it on this conversation: https://forum.corona-renderer.com/index.php/topic,13398.msg98910.html#msg98910
Title: Re: LUT
Post by: Juraj on 2017-06-22, 20:04:52
They work the same as long as you don't apply them in 32bit mode in Photoshop.

The way they are applied in Corona is hack of sorts, one I suggested they copy from VFB+ creator by extrapolating the range to avoid clipping the range which LUT naturally does (always).
By applying LUT inside Corona you're basically forgoing true 32bit linear post-production possibility anyway. It's applied in regular gamma space to what you currently see gamma-corrected inside viewport.

This is reason why other softwares like Vray, don't enable baking LUT into 32bit file (if you save .exr with LUT in Vray, the LUT (+ICC) gets ignored.

There really isn't much point to apply LUT to 32bit file in first place as it can't see that information nor output it.
Title: Re: LUT
Post by: Rotem on 2017-07-15, 19:35:13
There really isn't much point to apply LUT to 32bit file in first place as it can't see that information nor output it.

I don't know, the extrapolation trick seems to work pretty well, doesn't it?
Also, in VFB+ it's applied in linear space and then gamma in applied after the LUT, is it not the same in Corona?
Title: Re: LUT
Post by: Juraj on 2017-07-16, 16:23:25
There really isn't much point to apply LUT to 32bit file in first place as it can't see that information nor output it.

I don't know, the extrapolation trick seems to work pretty well, doesn't it?
Also, in VFB+ it's applied in linear space and then gamma in applied after the LUT, is it not the same in Corona?

For me it absolutely does :- ) But I don't do any further compositing in linear space, it just leaves me that additional dynamic range I might use sometimes. It was a general note as your (quite cool) invention is one-off rarity :- ).

The second question, I don't believe it is. I don't know how exactly it's done in Corona right now, but to yield 100perc. copy, you have to apply it after gamma in Photoshop. I guess Corona applies it after gamma (including contrast), and then converts back ?