Corona image editor saved images gamma

[Correntes]

Why i can´t open corona exrs saved from CIE in after effects ?
And why CIE exr are with the exposure and gamma completely off ?

Mind that i don't have any issue in after effects with corona exr and regular exr saved from frame buffer.

[JoeVallard]

I'm having the same issue as well. Opening EXRs (In Photoshop) saved from CIE looks as if the tonemapping isn't being applied and for some strange reason the hdri background is really dark. Checked the photo below, you can see in the PNG and EXR have less contrast and the highlights aren't getting toned down, as well as the background issue.

[Ondra]

yes, the tonemapping is not applied by design - the files are meant to be opened by CIE, and tonemapping is not baked in, so it can be changed in CIE

[JoeVallard]

yes, the tonemapping is not applied by design - the files are meant to be opened by CIE, and tonemapping is not baked in, so it can be changed in CIE

I'm opening up my renders in CIE, applying tone mapping, LUT, and denoising. Then clicking "Save All". The picture i posted is of the renders saved out in that format via CIE. In CIE i can't save them as EXR otherwise when i open them in photoshop none of the post processing I did in CIE is there and the HDR background is very dark. I've tried loading the alpha as transparency and alpha, neither work.

Last week i was having the same issue, but loading the EXR with the alpha as transparency seemed to work fine. The background was present and all the tone mapping was there.

If i'm not mistaken I installed the 1.6.1 hotfix this week, so that may have been the difference between this week and last week.

[mike288]

Hi, please, could you upload the CXR image so I can inspect it? Use our private uploader for that: https://corona-renderer.com/upload/

The save button saves EXR, PNG, BMP, or JPEG files with tone mapping (current element only), and CXR files with just tone mapping settings inside to be able to modify it in CIE any time later (all elements). The pixel data itself are not affected by saving into the CXR format.

[denisgo22]

standart exr. format saves from CIE also without Tone Mapping?!!!!
It seems that it is so---because There is a big difference between exr. saved from VFB and exr. saved from CIE??
In my opinion this should be the same thing:))
If this is so, then it is not very convenient for final editing and adding effects in PS and others third-party applications in 32bit colorspace:))

[mike288]

OK, I need some test data - please, can someone upload a max scene or CXR file for me so I can inspect the issue?

BTW, is LUT file correctly loaded in CIE (is it same as in VFB)? There is a bug (see https://forum.corona-renderer.com/index.php/topic,16462.msg103495.html#msg103495) that CIE fails to load LUT file sometimes. This should be fixed in next daily build.

[denisgo22]

OK, I need some test data - please, can someone upload a max scene or CXR file for me so I can inspect the issue?

BTW, is LUT file correctly loaded in CIE (is it same as in VFB)? There is a bug (see https://forum.corona-renderer.com/index.php/topic,16462.msg103495.html#msg103495) that CIE fails to load LUT file sometimes. This should be fixed in next daily build.

Ok///
I discovered the problem...
The problem in old,good 3dMax:)
Sometime the scenes from old collections even with INPUT Gamma 2.2, having OUTPUT Gamma 1.0////
During saving, cxr. file was saving with Gamma 1.0 /must be 2.2////
Also sometimes on creating NEW scene Max using old setting from previous opened project... if this was GAMMA OUTPUT 1.0, as this is a problem for new created project///
A big inconvenience than last version's of 3dmax all this parameter's of Output Gamma are hidden//and can't controlled directly via preferences menu///
Solution:--- using script "Gamma Setting" or something like this for all new projects, and make this for all old works:)

[alexyork]

OK, I need some test data - please, can someone upload a max scene or CXR file for me so I can inspect the issue?

BTW, is LUT file correctly loaded in CIE (is it same as in VFB)? There is a bug (see https://forum.corona-renderer.com/index.php/topic,16462.msg103495.html#msg103495) that CIE fails to load LUT file sometimes. This should be fixed in next daily build.

Ok///
I discovered the problem...
The problem in old,good 3dMax:)
Sometime the scenes from old collections even with INPUT Gamma 2.2, having OUTPUT Gamma 1.0////
During saving, cxr. file was saving with Gamma 1.0 /must be 2.2////
Also sometimes on creating NEW scene Max using old setting from previous opened project... if this was GAMMA OUTPUT 1.0, as this is a problem for new created project///
A big inconvenience than last version's of 3dmax all this parameter's of Output Gamma are hidden//and can't controlled directly via preferences menu///
Solution:--- using script "Gamma Setting" or something like this for all new projects, and make this for all old works:)

Can confirm. Huge annoyance.

[maru]

Here is how to set up gamma in newer versions of Max (scroll down to the very bottom):
https://coronarenderer.freshdesk.com/support/solutions/articles/5000515647

[denisgo22]

OK, I need some test data - please, can someone upload a max scene or CXR file for me so I can inspect the issue?

BTW, is LUT file correctly loaded in CIE (is it same as in VFB)? There is a bug (see https://forum.corona-renderer.com/index.php/topic,16462.msg103495.html#msg103495) that CIE fails to load LUT file sometimes. This should be fixed in next daily build.

Ok///
I discovered the problem...
The problem in old,good 3dMax:)
Sometime the scenes from old collections even with INPUT Gamma 2.2, having OUTPUT Gamma 1.0////
During saving, cxr. file was saving with Gamma 1.0 /must be 2.2////
Also sometimes on creating NEW scene Max using old setting from previous opened project... if this was GAMMA OUTPUT 1.0, as this is a problem for new created project///
A big inconvenience than last version's of 3dmax all this parameter's of Output Gamma are hidden//and can't controlled directly via preferences menu///
Solution:--- using script "Gamma Setting" or something like this for all new projects, and make this for all old works:)

P.S.---In addition to the foregoing...
During saving cxr. file from VFB don't exist option for change saving Gamma settings, as in regular saving menu of 3dmax, So it is not known with what Gamma settings cxr. was saving////
may be needed option for Controlling Gamma saving setting in File saving menu for Corona cxr. files:))

[denisgo22]

Here is how to set up gamma in newer versions of Max (scroll down to the very bottom):
https://coronarenderer.freshdesk.com/support/solutions/articles/5000515647

A big problem is--- "Automatically"---- not working in some cases:))

[JoeVallard]

Hi, please, could you upload the CXR image so I can inspect it? Use our private uploader for that: https://corona-renderer.com/upload/

The save button saves EXR, PNG, BMP, or JPEG files with tone mapping (current element only), and CXR files with just tone mapping settings inside to be able to modify it in CIE any time later (all elements). The pixel data itself are not affected by saving into the CXR format.

Uploaded an example CXR that was having the issue that i posted about. I checked my gamma settings and the ini shows exactly what was posted for recommended.

[TomG]

Been doing some testing on various issues, using the CXR uploaded by Jtveclipse12, here are my results so far:

- Is tone mapping done in the CIE saved to the various file formats?
It is for me, tone mapping done in the CIE definitely shows in the saved images in all formats.

- Why does the EXR look different?
What are you using to load the EXR into Photoshop? In my tests I have used EXR-IO. I do see a slight increase in contrast in Photoshop compared to the CIE (if I screen grab both and overlay them). I also opened the EXR in Qt4Image, and I see that it matches PS. If I open the saved EXR in the CIE, it looks the same as the original CXR looked (that is, "less contrasty" than the EXR opened in PS or Q4T). 32 bit EXRs can be handled a bit differently by different applications. We'll keep testing - let me know what you used in PS to open it.

- Why do EXRs saved from the CIE not open in After Effects?
It opened for me. Could a sample "problem" EXR be shared with us?

- Why does the background image change in intensity?
When the CIE saved the EXR, it premultiplies the alpha. This is what the standard for EXRs says - however, my understanding is that almost no other software follows that standard.

- Saving to PNG from the CIE
I have noticed one new thing here while testing. After Denoising in the CIE, if Blend is greater than 0.0, the transparency in the PNG is 254,254,254 for solid, and not 255,255,255 (in PS, can extract this info by Layer -> Layer Mask -> From Transparency, then turn off the RGB and view just the Layer Mask in the Channels, then use the colour inspector on the "solid" parts).

This doesn't happen if no Denoising is done in the CIE (save without denoising, or load a CXR that was Denoised in the VFB), nor does it happen from the VFB. We'll investigate further. The upshot there is that darker areas in a PNG may look a little less dark in Photoshop, as it is displaying a small portion of the empty checkerboard behind it.

Counteracting for that though, the PNG from the CIE is the same as the JPG from the CIE, and both are the same as how the image looks in the CIE. So only EXRs loaded into external applications show a slight increase in contrast.

- Handy hint!
If you post comparison images, could you post them as separate images please? It allows easy overlaying of each one and then flicking layers on and off to make differences more noticeable :) Thanks!

More info as we do more research, and any feedback, tests and input welcome too! Thanks!

[denisgo22]

Basically everything is fine, with correct setup scene in 3dmax /input-output Gamma settings/
I open in PS three versions saved to regular exr. file from CIE and it's the same////

But exist problem with Alpha channel///
If i open exr. file saving from CIE Beauty as Alpha channel, not transparent, i get this problem:



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It should be taken into account that with exr. file saving from CIE Lightmix always OKAY///
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