What I did:

With full production renders looming fast, I needed to make an informed decision about render settings and file format before committing to around 5,400 frames.

The Cryptomatte desaturation pipeline – isolating the IAM badge in full colour while the rest of the scene desaturates – requires OpenEXR Multilayer output from Blender rather than standard PNG renders. Before committing to this format across the full animation, I needed to understand the practical implications in terms of render time and storage.

Number of samples

I ran a direct comparison between 256 samples and 64 samples in Blender Cycles – the difference in quality was negligible when you consider it’s a moving picture – see images below. The render time difference, however, was a big jump!

On this sample:
64 samples = ~1 minute 21 seconds
256 samples = ~5 minutes 5 seconds

64 samples on left, 256 samples on right:

 

Slight loss of detail on bronze cat materials:

Subtle difference in shadows:

This made 64 samples the clear choice for production, taking into account the render time saving between the two settings.

PNG vs EXR filesize comparison

I then compared PNG and OpenEXR output at 64 samples. A single PNG frame came in at 3MB, while the equivalent OpenEXR Multilayer file was 23.9MB. Crucially, render time was identical between the two formats – the Cryptomatte pipeline adds no overhead whatsoever in terms of render time.

Scaled across the full animation — 5,400 frames at 3 minutes 45 seconds at 24fps — the storage difference is significant: 16.2GB for PNG versus 129GB for OpenEXR. However, with over 1TB free on my animation drive alone, storage is not a constraint.

What I learned:

The decision to use Cryptomatte with OpenEXR output is settled. Same render time, automatic badge isolation across every frame, no per-frame manual masking. The 8x storage overhead is the only trade-off and it’s not a practical problem. 64 samples is the production setting.

Next:

Hair modification for John’s age progression as a first step for my Alpha production animatic, then update the animatic with rendered scenes.