Author Topic: Color Difference between Corona VFB and render output  (Read 3112 times)

2025-06-21, 16:34:27

Wincowski

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Hi, my render output is different from the Corona VFB. I saved it as a PNG, and in the gamma option, I checked override as 2,2. Also, I saved with automatic gamma, but the result is also the same. There is no difference between automatic and override output. How can I save my render as in the viewport? It's urgent, please. Thanks

2025-06-23, 17:41:31
Reply #1

maru

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Sorry, but we cannot provide you with support for such an old version of Corona. Very likely, the issue is already fixed in the newest version. Please download it and check if you are still getting any differences: https://my.chaos.com/download/build?product=Corona
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2025-09-04, 15:38:29
Reply #2

Wincowski

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Hi, I update my corona to 13 and 3dsmax to 2026 but the isssue is still going on. I tried everything. First screenshot you see save as png, automatic and 2.2 overrride gamma, but still is not looking like the interactive render. I tried save 16bit tiff open in photoshop and save it, also it didint solve my problem. I open my render with 3dsmax file view image file, in 3dsmax its file, same as interactive render but outside of the 3dsmax, my renders washed out. This is a huge proplem for me. I am working according to the scene, arranging materials, models, maps all for the scene and the outcome has completely different colors.

2025-09-05, 19:14:35
Reply #3

Avi

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Hi,

Can you please send us a ticket for this issue so we can have a better look at your file setup and everything?

https://www.chaos.com/contact-us
Arpit Pandey | chaos-corona.com
3D Support Specialist - Corona | contact us

2025-09-14, 11:00:46
Reply #4

Adam

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Probs got to do with colour profiles of your monitor. Open your image in photoshop and assign your monitor colour profile to the image and convert to srgb.

2025-09-15, 17:49:17
Reply #5

maru

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We had some similar cases in the past. This comes from the fact that 3ds Max+Corona is not "color profile-aware". The most straightforward solution is switching your monitor to sRGB in its OSD settings.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2025-09-15, 21:42:58
Reply #6

pokoy

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We had some similar cases in the past. This comes from the fact that 3ds Max+Corona is not "color profile-aware". The most straightforward solution is switching your monitor to sRGB in its OSD settings.
/rant mode

Which is the worst of all possible suggestions - sorry for that.

What every unexperienced user (unexperienced in terms of color management) gets wrong is that OCIO is dubbed color management in Max while in reality, it's a rendering space + tone mapping, which has *nothing to do with managing colors as in 'make sure the colors look the same across all my apps*. This is partly due to user ignorance, hidden settings in Windows, partly due to 3ds max who don't care about PS and print, and finally Corona devs who just can't be bothered to finally implement a final ICC-based transform in the VFB and embedding that ICC profile (chosen by the user) when saving files, even after all the posts asking why colors don't look the same in PS/Windows.

Let's see how long until the next user is asking the very same thing, only to be told that sRGB is the way to go (which it isn't, it's just an additional display of ignoring the fact that Corona could and *should* solve it right in the VFB/file).

/rant mode off

2025-09-15, 21:48:35
Reply #7

pokoy

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And if you want to see this finally solved (or at least mitigated by ensuring color fidelity using a 30+ years old standard by the name of ICC profiles), vote for it:

https://chaoscorona.ideas.aha.io/ideas/CMAX-I-152

Yesterday at 08:34:27
Reply #8

piotrus3333

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much needed rant.
thank you.
Marcin Piotrowski
youtube
CGI OCIO config 04

Yesterday at 15:19:21
Reply #9

pokoy

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@Maru - I hope this didn't come off as offensive, but here's a good reason not to suggest:

A) In case OS uses sRGB, just assign sRGB in PS (and optionally convert to whatever space users wants to work in)
B) In case user is using a calibrated display or uses a manufacturer display profile, assign that profile to your document in PS (and optionally convert to whatever space users wants to work in)

Reasons for not suggesting A
- I might use a calibrated device > suggesting sRGB results in wrong colors
- I might use a display that came with some installer which silently installs a generic display profile for the display (and user might not know it) > suggesting sRGB results in wrong colors
- I might switch my main display, old one was uncalibrated, new one comes with calibration profile... same wrong suggestion

Reason for not suggesting B
- When calibrating, the resulting display profile will change slightly every time a display is calibrated. The reason for this can be an aging display, user error, calibrating device picking up ambient lighting and making the calibration dependent on daytime or room lighting while calibrating, and profiling intent (for example having profiles with different target brightness to accommodate for different lighting conditions for postproduction people working in the studio or on site of production).
In case of an aging device, which will inevitably occur, my display profile is *different* from the one I've used a few months earlier. It means that assigning the profile 6 months back will not look the same when I re-render the job now and assign my current - now slightly different - profile. The display profile of a calibrated device will inevitably change over time if user cares enough to re-calibrate every given time span. If I don't re-calibrate I lose color fidelity, so one of my responsibilities in a color-aware working environment is to make sure I re-calibrate ragularly (or 'validate' the profile as it's called).
- Similar argument as above, I buy a new display. Both were calibrated but the new one is obviously technically better. Both calibration profiles will look vastly different when assigned to the same image. The profiles are all right, but they correct for a very different base scenario, and they will not be identical, resulting in different colors when following the advice.

And here's where Corona development can help. Please please please finally add a final color transform to the VFB that would allow the user to assign a profile just like PS/AE do it.
I've had the discussion with some devs in the past and the argument against it was that they would need to take care of input maps and color values... no, you absolutely don't!!
Sure you could do it, but only if you needed to convert color values from one space to another, which you don't!

Here's an example:
Important preface for those who aren't aware - color profiles don't change the pixel values, they add a color transform for the device output *only*.
Let's say I'm using AdobeRGB as my main profile for ALL my work. I have my textures and backgrounds prepared in PS using AdobeRGB.
I load them into Max, which ingores it, uses either sRGB or my display profile to display them, and yes, they look like shit.

BUT, the moment I render them, and have the VFB apply a display transform to AdobeRGB, they look exactly like what they looked like in PS. (Let's ignore the OCIO or ACES tonemapping operator for the sake of the argument I'm trying to make). If I save the file, and the profile I chose in the VFB will be embedded in the file, I will have the same colors I had in PS originally, and how the VFB displayed them wherever I'm looking at them (PS or Windows).
(Whether or not the profile is embedded is not important, but I'll know that what I see in the VFB will not be the either crippled sRGB crap or overly saturated wide gamut output of a pro-grade display but proper AdobeRGB I'm using in PS, too.)

Yes, they won't look like they do in PS in the viewports etc, because that's the 3dsmax part and they chose to ignore ICC entirely. Yes, OCIO might falsify this and tone mapping will do another round of 'damage' to my input, but that's not the point. By giving the user the option you would do *your* part.

This way, I gain the ability to see my intended colors in the VFB and frankly, that's what I care about the most.

The creator of VFB+, a nice VFB plugin from ancient times when renderers didn't come with their own VFBs and postprod options, integrated ICC display transform in a weekend. And he struggled most with CMYK conversion which you wouldn't have to care about at all. It really was a matter of a few days.

Or... you guys can just go on with the common bi-weekly post about 'my colors look different in PS', not caring about pro users who really need color fidelity in their pipeline and ask for it since years, and not educating people and giving them wrong advice instead. I could go on and on... it's just frustrating to see how this gets ignored.

I'm open for discussing this problem and how to overcome it in another place if needed, be it a new thread or discord. It's high time this gets solved as far as can be done on Corona's side.
« Last Edit: Yesterday at 15:31:29 by pokoy »

Yesterday at 16:24:13
Reply #10

Aram Avetisyan

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Hey,

Thanks for bumping this, even though it has been bumped many times.

I will just say that anything regarding the file output is, unfortunately, handled by 3ds Max, we use its dialog for the output. We are limited to its capabilities. View transform may be quick to implement, but a whole new independent output dialog is not.

Let's hope that 3ds Max development handles this at some point, and there will be minimal work to sync on our side. If not (like when we implemented ACES OT for the sake of it, then Color Management with various view transforms got introduced :)), then the only way is having our own output dialog. We do have some, though indefinite, plans for this for future versions.
Aram Avetisyan | chaos-corona.com
Chaos Corona QA Specialist | contact us

Yesterday at 17:27:45
Reply #11

pokoy

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I will just say that anything regarding the file output is, unfortunately, handled by 3ds Max, we use its dialog for the output. We are limited to its capabilities. View transform may be quick to implement, but a whole new independent output dialog is not.

No problem - user knows what profile he's used, after all the user chose the ICC transform operator (if there ever will be one) and assigned it a profile. No hassle in assigning the same in PS manually. In that case, Windows wouldn't know what the profile was of course, still, that's the smaller harm. I'd rather have something that works in the pipeline than nothing because Windows doesn't know what to display and falls back to sRGB.

Let's hope that 3ds Max development handles this at some point, and there will be minimal work to sync on our side. If not (like when we implemented ACES OT for the sake of it, then Color Management with various view transforms got introduced :)), then the only way is having our own output dialog. We do have some, though indefinite, plans for this for future versions.

I think I can answer this for you - there will be absolutely no action from the 3dsmax team to support ICC natively. After all they sat on the topic for some 20 years despite numerous requests.
They implemented OCIO only because they acquired Arnold and the 'physical' exposure and tone mapping stuff they had from mental ray days was just the worst imaginable workflow you could come up with. And, sadly, when OCIO was implemented, there was almost no user feedback despite the importance of the subject.
When I asked specifically about ICC support, the answer from the mastermind was 'I've heard OCIO 2.0 supports ICC profiles, but honestly, I have no clue... By supporting OCIO anyone else can build their own stuff on top of it'. They don't care about ICC, simple as that. They cared about ACES though, and that was a forced move because they needed Arnold to work in common VFX pipelines and look the same, and the VFX world cares about ACES these days, nothing else. You won't see ICC touched by the 3ds max team for another 20 years.