Color Discrepancy Issue with Cryptomatte in PNG

[Guillaume G.]

Hello,

I have a recurring issue when using Cryptomatte: the colors in the saved file are very different from what is displayed in the VFB, which makes the file unusable (see attachment). I don't encounter any problems when saving in CXR/EXR, but sometimes it's much more convenient to use a PNG directly, so I would like to understand where the problem comes from and what I might be doing wrong.

Thank you!

[TomG]

The colors shown in the VFB are NOT the cryptomatte. Those are just a quick visual representation, and should not be used for masking etc. in post. Not even when saving to CXR / EXR :) That is still not the actual cryptomatte. It's there just to let you know cryptomatte is working and give you some idea of how it is dividing things up depending on how you have it set.

Instead, once saved as CXR (and renamed to EXR) you will find when using EXR-IO (without it, Photoshop won't load the file properly) that there is a separate layer for each... well material or object for example, but it depends on what you selected for the cryptomatte. Those individual layers are the actual masks that should be used in post.

You can see them in the video at

t=204 - and indeed you should watch the whole video. That color pass / element should just be thrown away and never used other than as a check on "is cryptomatte working?" when rendering :)

[Guillaume G.]

Thank you, Tom, for your response :)

As I mentioned, I’m well aware of the "real" functioning of Cryptomatte. I just thought that the view in the VFB could also be used as a backup solution (even though I know it’s not the proper way to do it). It seems to me that it was usable in the past, but I might be mistaken.

In any case, noted—goodbye to the VFB colors. Thanks :)