You've Been Inform'd Ep11: My mom thinks I'm a Grain Angel, but I don't want the halo

Hello People,

Here is a deep dive in to the cause of grain halo, and some different ways of dealing with it.


It’s longer than Barry Lyndon, but I’m excited to see.

Thanks for taking the time to show that @ALan, very interesting.

Its the Gettysburg Address of Grain and it’s great. Thanks @ALan some great techniques here. One question: given that it looks like you have the Silhouette ML degrain/regrain node… is there any need for manually building this anymore or does the ML tool not work as advertised?

I’ve not tested the ML Degrain at all, we’ve used NeatVideo for years.

With dasGrain, I wouldn’t say this all becomes pointless, you just have to work less hard. For instance maybe just the grow->diffuse->posterize instead of the other more complex techniques.

This is fantastic.

It does focus primarily though on the grain halo at the edge of the comp. Isn’t there also a second problem with grain being sometimes different in highlights and shadows.

I’ve come across this: You have a shot where there’s an actor with some bright clothing that’s standing in front of a dark background. They decide this actor has to be painted out. In the stolen grain scenario you’re now taking grain that originated from highlight exposure and is now being added back into a shadow exposure. That leaves a bit of the outline of painted out content in the structure of the grain if you use the based stolen grain. Maybe that’s the part of the puzzle that divide/multiple handles better than subtract/add, as it’s compensates for the brightness of the before/after? Of course it also gets taken care off in grain algorithms that sample the grain from elsewhere in the shot and then tile it across (without seams), as you’re not putting the old grain from the painted out area back where it was.

Yeah. That is why I state in the beginning that the video is about grain integration and not generation. That could be a whole other video. Since dasGrain came via Silhoutte, and it is a superior solution for generation, I’m not all that interested exploring this topic.

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Fantastic @ALan and very clearly explained.

Thank you.

Super interesting. Thanks for taking the time to do this @ALan

I’d love to see some videos from you guys on how you deal with this topic.

Yeah? My video would be very short. Mostly working on commercials but the problem still exists.

I prefer to use the Autodesk regrain and I sample and view each colour channel separately. Then I’ll use a 2D histogram to crank up the matte.

I can spot soft or static grain on a comp but no one is being so militant as to check back to make sure the grain is exactly the same :sweat_smile:


Thanks for the brilliant vid Alan. Here’s my contribution, some deniose, renoise and noise patch tricks, all working from the orig camera noise.

The compression on YouTube might make some of these fine noise elements hard to see, so maybe watch it set to a high res

I did this in ACES, but the same techniques will work in any colourspace.

Here’s the batch setup and the same as a mini archive if anyone want to use it. Sorry clip not included.
It was done in 2024.1, so sorry to anyone not on that version yet.