What is the difference between the frame buffer’s highlight burn and a burn value in the Color Mapping? Other than burning it into the image using the Color Mapping?
I think its mostly the same. But one difference I know, when you use burn in VFB, bloom and glare still use bright pixels and these effects work great. When you use burn in color mapping settings, bright pixels will be darker for bloom/glare too and this effects will be much harder/impossible to set up properly.
Yes, I found that part out. I also found that things do render faster with Color Mapping Burn on, but not when using the VFB. I guess like anything, there are pros and cons.
set the color mapping burn to a low value -.3 or so, and change mode to ‘none’ so it doesn’t bake it in to get the best of both worlds.
We do our color mapping in post after applying glows, i set up a fusion macro which is a little like the VFB with a glow, color balance, highlight compression & curves - it works great and offers a lot more flexibility to tweak.
I did an interior with a burn of .3 and it was really flat and I lost ability to change exposure in PS. I’ll try setting it to none.
Use the burn value in the vfb when you have it set to none, itll be burnt out otherwise. The render you save out will be as if the burn is at 1, but the sampling and AA will have been performed as if it is .3
Hey @Neilg Any chance I could have a look at your fusion macro?
When you change it in color settings, you cant change it interactively. This is why its much better in VFB.
Would love to have a gander at this, if you would be so kind? 
jep, i’d also be interested.
Whilst we are on the subject on burn, something that has been bothering me for quite some time, is how to target blown out highlights when working in lwf.
One thing that Camera Raw in PS is good at (was good should I say since they removed its 32 bit editing capabilities forcing you over to LR, spits), was specifically targeting the really bright highlights within an image and toning them down in 32 bit. I’m aware this question has been brought up a few times down the years on here (using search) but I still haven’t quite figured out how to have some control over it all.
See attached images. Quick example.
So from left to right, we have the blown out beauty pass, the same beauty pass with an exposure reduction (to reveal texture the information is there), and an image with a reduction of the highlights using the VFB. Whilst the blow may be physically accurate, I’m sometimes asked by clients to tone this down so we can see the material/texture, as represented in the reduced exposure image I’ve attached. Highlight burn, just looks ugly. What I want, is to be able have a beauty pass, and target that blown out area, reduce the exposure of it, to reveal the information that is there in 32bit, without affecting the rest of the image too much. This was possible in camera raw (even with that annoying curve adjustment i throws onto an image when used).
At the moment I have to create two versions of the beauty pass in PS, and use masks etc to achieve this (ala the fourth image upload). This ok for the most part on a simple scene like this, but when they are everywhere it becomes a bit messy!
If speed isn’t a factor then it makes sense to stay in the VFB, however, when I use the Color Mapping burn is where I see speed savings.
I am planning to make a post about the entire setup, but the most important part is the tonemapping tools - I have 3. I did not create them, I collected them from forums.
Edit “MacroOperator” to “GroupOperator” if you’d like to unpack them and fuck around with the non macro version.
Hit the post limit, so they’re at links
Reinhard - Paste2.org - Viewing Paste jsZhjapH
Corona highlight compression (very simple, good results) - Paste2.org - Viewing Paste KKmpsMMz
Filming tonemapping (complex but powerful) - Paste2.org - Viewing Paste LChgB58b
And an exponential glow (put this before the tonemapping. it’s not quick but it’s beautiful) - Paste2.org - Viewing Paste F9994E8E
DanSHP - can you share the raw exr of your first image? i’ll see if these can handle it.
edit2: here’s a quick comparison on an old test. it’s not great but should give an idea of what they do. The real benefit comes from making color and level adjustments to objects using multimatte masks before color mapping and glow is performed - gives a much more reliable result. The glow is a bit crap, i didn’t edit any settings and it is catching on too many things.
I’m so hoping that the addition of the new VFB in one of the service packs will also bring some new tonemapping options. This is an area where V-Ray is way behind Corona, and miles behind fStorm, which has some of the nicest color mapping options of the current renderers.These days I spend less and less time correcting images in PS, I tend to do everything with the VFB and applied Luts. This however never gets baked into the image when saved, so you have to use the nasty Clipboard-workaround, which doesn’t work in animations…
Sorry for the late reply, i was away from the office for a few days. See attached zipped .exr. Will this do?
Test.zip (6.96 MB)
I’m unable to download the links you’ve posted, as they are blocked by our IT network, but I think I’ve come across these tone mapping macros before. Are you referring to these? https://corona-renderer.com/forum/in…p?topic=1807.0 and here Racoon Artworks
I’ve just thrown the same .exr i attached previous to this into Fusion and played around with the sliders, and I’m not getting much functionality (similar to PS camera raw highlight reduction).
so, just so I can get my head around this.
- You render out an image with no colour mapping (i’m assuming with no VFB corrections too)
- Take the image into fusion and tonemap there?
- You are using multi mattes to target areas of an image that has blown out areas?
I think the values in your test are just a bit too far apart, rgb values in areas are 17/18+. you’ve got a tiny hole only letting in direct light - no environment at all, which is powerful enough to then light up the entire room. I have to set the RGB gain to 0.05 to even see any detail in the bright area.
tone mapping wont save you in this situation - it pulls back blown out areas but if you shot this with a real camera you’d have to bracket 9+ shots.
At least if you use fusion, its node based for creating masks? you can recreate what you were doing in camera raw with curves & cc tools
Ugh, this just goes on and on around in my head and I never get anywhere with it. Frustrating and mildly depressing.
I know that if I could take that 32bit ext in PS camera raw, I could reduce that blown out highlight down to a level I could see the information, without using masks anywhere, without layering multiple reduced exposed layers ontop of one another. There has to some way to mimic camera raw in another program so i can target the highlights.
Maybe I’m going about this completely the wrong way, I’m really not sure but I’m starting to think I don’t actually have a clue what I’m doing anymore !
I think I’ll just start a thread, with my basic set up for an interior and exterior, and others can can give me some advice.
Starting a thread is a good idea - with a different lighting setup you wont be encountering such extremes.
For what it’s worth, fusion can mimic what camera raw is doing and pull down those highlights using the regular curves and cc tools - it’s just not tonemapping. I would still look into alternate lighting setups though.
