Author Topic: Different Colors Between Corona VFB and Saved Image  (Read 2209 times)

2025-02-13, 17:22:18

DLieber

  • Users
  • *
  • Posts: 3
    • View Profile
Hello,
Hope you guys are doing all right.

I'm using Max 2025 and Corona 12. In the Corona VFB, the render looks fine, but when I save it, the colors appear very different.
Can someone please help?
Thank you,

Daniel

2025-02-13, 17:48:42
Reply #1

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 13461
  • Marcin
    • View Profile
Could you share a screenshot showing the difference? In what format are you saving your renders? In what application are you viewing your renders?

Also, what are your color management settings in 3ds Max? Please check if you have them set as in the attached pictures.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2025-02-13, 18:00:50
Reply #2

DLieber

  • Users
  • *
  • Posts: 3
    • View Profile
Hello, Maru.

I use Gamma Workflow 2.2 Color Management. Should i use the OCIO-3DMax Default? What´s the difference between then?

I changed the photoshop color management to my monitor´s one (DELLU3223QE) and it worked fine.

Thank you!
Cheers
Daniel


2025-02-14, 09:01:16
Reply #3

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 13461
  • Marcin
    • View Profile
I use Gamma Workflow 2.2 Color Management. Should i use the OCIO-3DMax Default? What´s the difference between then?
There is no right or wrong here. Gamma is na older workflow, but it is also less likely to cause any trouble. You can learn about both modes in the 3ds Max help https://help.autodesk.com/view/3DSMAX/2025/ENU/?guid=GUID-DA8CE2F5-1400-45A9-BFCF-A4A8968175CF

Quote
I changed the photoshop color management to my monitor´s one (DELLU3223QE) and it worked fine.
Then I guess case closed. :)

Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2025-03-03, 11:52:45
Reply #4

piotrus3333

  • Active Users
  • **
  • Posts: 295
    • View Profile
I changed the photoshop color management to my monitor´s one (DELLU3223QE) and it worked fine.
Then I guess case closed. :)

how is it possible that Corona team is still misinforming users on this subject?

"case closed" above means: you've just turned off colour management in Photoshop so it matches non-managed Corona. and in the process you used a profile made for your type of display so it sounds correct. right?
Marcin Piotrowski
youtube
CGI OCIO config 04

2025-03-03, 11:59:38
Reply #5

piotrus3333

  • Active Users
  • **
  • Posts: 295
    • View Profile
read Photoshop manual.
read what D Fosse writes on adobe support forums.

your default settings Photoshop shows the right colours if your image from Corona is srgb tagged.
your default Corona does not show it correctly.

Marcin Piotrowski
youtube
CGI OCIO config 04

2025-03-03, 12:01:25
Reply #6

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 13461
  • Marcin
    • View Profile
Does this sound better?

The reason why there are differences between the VFB and the saved image previewed in Windows viewer or Photoshop is that 3ds Max and Corona are not color-managed or "color-profile aware" while the viewer and Photoshop are.
 
I was able to find two solutions on the Corona forum:
 
This is more of a workaround, but it works, in the sense that you will get identical appearance of the image in the VFB and after saving it:
https://forum.corona-renderer.com/index.php?topic=27672.msg182592#msg182592
You need to assign the color profile that you have in the Windows Color Management (e.g. "DELL U2724D Color Profile") to your image in Photoshop. I used a different color profile just to test this, but the point is to use the same color profile in Windows and in Photoshop.
 
The "proper" solution, which is only available for monitors which support it was shared by Juraj Talcik here:
https://forum.corona-renderer.com/index.php?topic=27672.msg182552#msg182552
 
"To have identical and correct colors between 3dsMax/Corona VFB and Photoshop, you need to physically clamp color space (space, not profile describing one) of the Display down to sRGB. That needs to be done on hardware level, in monitor OSD menu either through factory calibrated profile (the Monitor stores 14bit 3D LUT, not ICC profile) or custom hardware calibrated profile (again, stored as 14bit 3D LUT internally in Monitor OSD, not in Windows).
 
BenQ PD3200U doesn't offer hardware calibration, so you are stuck with factory profile which is ok because it's pretty good.
 
This is correct workflow for this monitor for 3dsMax/Corona.
 
1) Monitor OSD Menu: Select sRGB mode. Then adjust brightness to your liking. (Fun fact: Calibration is also done to exact brightness levels, but if you move it +/- 50perc. the difference in accuracy is not drastic).
2) Type Color management into taskbar in Windows, select your monitor, check "Use my settings" and select "sRGB" ICC profile. Set "Use as default".
3) When loading any rendering into Photoshop, you don't need to do anything if your settings are set to "Don't Ask". It will stay unmanaged and you only need to "Assign" sRGB profile at the end of export, for example when saving to final file. Don't convert to any other profile.
 
The above workflow doesn't work for high-gamut displaying (DCI-P3, HDR workflow,etc..) or printing (AdobeRGB, LAB,etc.). But since 3dsMax & Corona are not color managed (Autodesk Maya and Vray for example are), this is the best scenario to use right now. Least headaches. Colors are always correct, you're just not using wide-gamut capability, which is ok since most devices are sRGB only, even today."
 
So to conclude: the issue is caused by the fact that 3ds Max and Corona are not properly color-managed. If they were, the images would come out the same. The workaround is to assign your monitor's color profile to your image in Photoshop. The proper solution is to enable the sRGB profile in your monitor settings (if available) and in the Windows Color Management settings. Then you need to assign the sRGB profile to the final images you are saving from Photoshop.
 
If color accuracy is crucial for you and you want to avoid all the hassle, you may want to consider switching to V-Ray, which is color-managed.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2025-03-03, 12:17:52
Reply #7

piotrus3333

  • Active Users
  • **
  • Posts: 295
    • View Profile
Does this sound better?

The reason why there are differences between the VFB and the saved image previewed in Windows viewer or Photoshop is that 3ds Max and Corona are not color-managed or "color-profile aware" while the viewer and Photoshop are.


spot on.
Marcin Piotrowski
youtube
CGI OCIO config 04

2025-03-03, 12:24:42
Reply #8

pokoy

  • Active Users
  • **
  • Posts: 1974
    • View Profile
My 2 cents - while Corona has followed the 3dsmax development with OCIO, you also omitted the work case most users will face just like Autodesk did, namely going to PS and work on the images - where ICC profiles count, not OCIO view transforms. OCIO might support ICCs but so far I've only seem convoluted ways to get there and it's nowhere near user friendly.

The only way to solve this really common problem would be to finally implement ICC profiles in the VFB, and embed them in the files saved.

I've been asking for this for years and I believe you really have to consider finally adding ICC functionality. It would finally make it possible to preview images the way they'd display in PS.
Most users would already be happy with only adding final VFB transform (not taking care of any input conversion for textures, or only on some general global level, not per texture).

2025-03-03, 12:50:10
Reply #9

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 13461
  • Marcin
    • View Profile
Could you please log the ICC support (and any other color-management requests) at https://chaoscorona.ideas.aha.io/

Thanks!
« Last Edit: 2025-03-03, 13:04:57 by maru »
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us


2025-03-03, 12:59:37
Reply #11

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 13461
  • Marcin
    • View Profile
Ok, I will need to dig deeper and make sure this is internally logged both for C4D and Max.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2025-03-03, 13:00:34
Reply #12

piotrus3333

  • Active Users
  • **
  • Posts: 295
    • View Profile
and I don't think suggesting pokoy to log something again for you is a good idea. I guess he did that in 2015:
https://forum.corona-renderer.com/index.php?topic=9346.msg60702#msg60702
Marcin Piotrowski
youtube
CGI OCIO config 04

2025-03-03, 13:04:49
Reply #13

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 13461
  • Marcin
    • View Profile
Yeah, I get it. The thing is that anything that is a feature request should go through the AHA portal nowadays. But I will take care of it, no worries.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2025-03-03, 13:30:55
Reply #14

pokoy

  • Active Users
  • **
  • Posts: 1974
    • View Profile
Lol, I've been asking for this in some other places, too. Some time around Corona 1.4 or 2 I just gave up because I realized the team just didn't *understand* the need. For some reason, dealing with support requests, confuse users for years only to still offer nothing seemed like the better way to go about it.

Just so you know, since piotrus3333 linked to my post, it took Rotem literally a weekend to implement this in VFB+, and most of the time he spent on dealing with RGB to CMYK conversion, which we wouldn't need, let's just do RGB. And 2015?!? 10 years...