EXR file format for saving frames with numerous passes:

[darawork]

Hi all,

I was looking up about the EXR file format for saving multiple element pass from Corona 7 into Photoshop 2022 in a container file format. It's looking like a pretty good solution. I used to use TIFF before sometimes, and other times just single element tiffs with alpha.

I was reading about linear and non-linear workflows, and gamma 1.0 as opposed to 2.2 (or -.043 even).
It's a very deep subject to research, but interesting.

OpenEXR was originally developed by Industrial Light & Magic (ILM) about 18 years ago and made open source. Anything made by ILM staff is usually top notch, and they use it still themselves.

Does anyone here use it, and perhaps have any tips for things to look out for, limitations etc? One thing a member of our team noticed was that he couldn't get the Alpha working properly in After Effects, but I'm sure that's just an After Effects routine that needs to researched a but more.


How do people here use EXR format in their rendering pipelines?  I'd be interested to learn more about it, in different case scenarios, especially using something like Corona.

Thanks 🙂

[CiroCardoso3v]

EXR is the file format to go. Some people will complain is too big in terms of MB, but if you compare it with TIFF and even TARGA isn't that bigger. My advice is when rendering make sure you use half float 16 bits, which is more than enough.

I don't think Corona supports EXR Compression, but with Arnold I usually compress the EXRs with DWAA or DWAB while working with any AOV that isn't data. This means that anything like Z-depth, Cryptomatte, or P, I use the Zip Compression.

It is worth investigating if AE works better with single-channel or multi-channel EXR files. With Nuke multi-channel works just fine, but with Fusion I noticed some issues and slowdowns.

However, in Archviz and using Corona, you will probably hear a lot of people saying that is a waste of space to use EXR. I know some London Studios that render their animations .... in JPGS. 😑

[darawork]

Hi,

Thanks for the detailed reply.
Unfortunately our IT department has determined it is 'not to be used in a professional setting'.
Personally I put this down to the 'flashy' nature of the EXR-io website and not to do with its core functionality.
Anything to do with 'gaming' or similarly looks like it has anything to do with gaming usually gets shot down.
I'll give it a go at home instead.

Just a side note, Corona render does support EXR format quite well. They even have their own CXR format based around it. A render can be stopped, saved as a CXR, and then restarted from where it last left off, which is handy. As for in-software compression, yup, it seems to have some good functionality there too;

Yup, I can bring EXRs from Corona into AE alright, it's just I wanted to try them into Photoshop directly.
Photoshop can open EXR files, but translates them into a single layer, not a multi-layered file unfortunately.
They must also not 'like the look of' the EXR-io website.

I was thinking 16bit was the way to go alright, 32bit is overkill in most cases.
I'll give it a go at home anyways,

Thanks 🙂

[CiroCardoso3v]

Yes the CXR file is just a glorified EXR. For photoshop, I usually use EXR-IO, but most of the time I am working with Nuke so isn't a big issue for me. In terms of EXR compression, you can compress the files after being saved.

https://www.artstation.com/marketplace/p/gGKA/exr-compression-vfx-grace