Diffusion (not blur) Methods

[Yellow_]

I'm looking at a combination of local contrast adjustment / natural tonemapping / diffusion (not blur) / add grain methods.

With regard to diffusion, I'm looking for any avisynth script or functions that can be used to diffuse rather than blur, the sort of diffusion that is seen printing to paper, subtlely though and suitable for video moving imagery not some nasty photoshop filter type effect.

Not sure whether something like addgrain or Mohans HQDefocus offers this.

[SSH4]

please show any examples

[Yellow_]

Probably any frame from the last two Harry Potter Movies or any one of the Lord of the Rings Trilogy:-)

http://www.beyondhollywood.com/harry-potter-and-the-deathly-hallows-part-2-2011-movie-review/

And my queries are inspired by a podcast interview with Peter Doyle here:

http://www.fxguide.com/quicktakes/peter-doyle-on-complex-feature-film-grading/

Where he discusses some of the techniques employed with Baselight. As an aside, I love his quote about "who ever said grading had to be with a 1D LUT and basically been a 1D look up table jockey" paraphrased.

Don't expect anyone to sit and listen to the podcast for my benefit with this post, so I'll try and transcribe the bits relevant to my query.

[Dogway]

I had my filrts with color grading and compositing so Im interested, do you know where can I listen to the podcast?

Im not sure what do you refer but it might be the bleach bypass effect? Its an effect done on the film negatives. Look for SelSah_v2 or the functions made by WorBry but you might better use a dedicated software for that.

[Motenai Yoda]

do you intend a sort of bloom effect?

[Yellow_]

I had my filrts with color grading and compositing so Im interested, do you know where can I listen to the podcast?

hi Dogway, I'm sorry I see the link is now dead, I've had it on my ipod for sometime. Looks like it's only available through iTunes. :-(

Im not sure what do you refer but it might be the bleach bypass effect? Its an effect done on the film negatives.

Not really, this is more about wider techniques.

He does talk chemical processing as well, but diffusion was to do with the fact they shot wide with deep depth of field, then rotoscoped the characters in a simple way not articulated mattes, as he says "on a plane of focus", deciding what piece of scenery or element in the scene to be the point at which to go out of focus, then diffused the background to emulate a shallow DOF but diffused rather than blur because blur was detrimental to contrast ratio and chroma?

I really need to transcribe to make more sense.

Look for SelSah_v2 or the functions made by WorBry but you might better use a dedicated software for that.

Ok, have seen that before but will look at it again.

@Motenai Yoda

Bloom would be a nice addition.

[Dogway]

Normally filmmakers tend to pronounce shallow DOF to bring things out and give it that dreamy look. What I observed in the pictures is crushed blacks (a hint for bleach bypass), chroma smearing like watercolors, and that green on the darks plus reds on the brights. An idea I had is to blur/expand the neutral tones, say from 96 to 164 with a gradual mask.

[Yellow_]

Normally filmmakers tend to pronounce shallow DOF to bring things out and give it that dreamy look.

I'm one of those, f1.4 + variable ND always. :-)

What I observed in the pictures is crushed blacks (a hint for bleach bypass), chroma smearing like watercolors, and that green on the darks plus reds on the brights. An idea I had is to blur/expand the neutral tones, say from 96 to 164 with a gradual mask.

Yes, though he talks more of local contrast enhancement & local rather than global tone mapping methods.

Old way to do the LCE with film was to make a black/white duplicate of the frame, overlay it and mix between the two to get a desaturated look.

Another thread I started is looking for LCE methods too. :-)

[Dogway]

Old way to do the LCE with film was to make a black/white duplicate of the frame, overlay it and mix between the two to get a desaturated look.

I always thought that was the way to emulate the bleach bypass in software. I will have a look on the other thread.