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Variable Diffusion Frequently Asked Questions

Apr 23, 2018 by Invisible Chainsaw

Are you planning to release a Windows / After Effects version of Variable Diffusion?
Are you planning to release Variable Diffusion as a plugin for other host applications like Final Cut Pro, DaVinci Resolve, Avid Media Composer, Vegas, or as an OFX plugin?
What are the proper project settings for using Variable Diffusion?
Can I use Variable Diffusion to generate a LUT (lookup table) or CDL (color decision list) to apply in other software?
Do you have more Stylized Looks presets available that aren’t quite as garish and colorful?
Does Variable Diffusion take advantage of After Effects' 32 bits per channel (float) mode?
Will Variable Diffusion’s Real Filter Emulation presets yield exactly the same results as using real, physical filters?
For some types of shots with heavy Variable Diffusion settings applied, like pans and handheld moving shots, I’m getting a “twinkling” or “pop off” effect around bright objects just as they are moving offscreen, similar to the way lens flares behave. Is there a way to minimize this “twinkling at frame edge” behavior?

Are you planning to release a Windows / After Effects version of Variable Diffusion?

Currently it is only available for Mac / After Effects. If there seems to be demand for a Windows version we will strongly consider it.

Are you planning to release Variable Diffusion as a plugin for other host applications like Final Cut Pro, DaVinci Resolve, Avid Media Composer, Vegas, or as an OFX plugin?

If the demand is there, we’ll strongly consider it.

What are the proper project settings for using Variable Diffusion?

In order to produce naturalistic-looking “optically intuitive” results, Variable Diffusion requires two specific features enabled in your project settings:

  1. Color depth set to 16 bit per channel.
  2. "Linearize working space" turned on. You’ll notice that in order to enable "linearize working space", you will first need to select a working space. For 99% of all projects, the appropriate option is "HDTV (Rec. 709)."
    The After Effects project settings can be accessed at (top menu bar) File > Project Settings (usually at the very bottom of the dropdown menu).

Can I use Variable Diffusion to generate a LUT (lookup table) or CDL (color decision list) to apply in other software?

No, unfortunately that won’t work for either LUTs or CDLs. That’s because Variable Diffusion doesn’t simply shift the color values of individual pixels, it alters the color of individual pixels based on their relationship to other areas of the image (just as real glass diffusion filters do).

Do you have more Stylized Looks presets available that aren’t quite as garish and colorful?

The Stylized Looks presets can be easily dialed down via the “Blend with original” slider in the plugin’s effect controls (the very last of the controls). Just going halfway at 50% will bring many of the colorful presets to a more sophisticated look. Also, you can easily change the coloration to be less saturated, or any color you like, within the “Colorize” effects controls.

Does Variable Diffusion take advantage of After Effects' 32 bits per channel (float) mode?

No, because it will not access or preserve over-bright and under-dark color values. Variable Diffusion is designed to be used in 16-bit per channel mode with "Linearize Working Space" turned on. When working in a project set to 32 bits per channel (float) mode, it will function the same as it would in 16 bits per channel mode. Because of this, we recommend that Variable Diffusion be applied in your process after any intensive compositing that requires 32 bits per channel (float) mode.

Will Variable Diffusion’s Real Filter Emulation presets yield exactly the same results as using real, physical filters?

No. When you use real physical diffusion filters, you’re sampling light from the real world which contains much, much more image information that any recorded image of it. We feel our Real Filter Emulations come very close to the look of physical glass diffusion filters and capture the “feel & spirit” of them, and do so closer than any other dedicated post production product, thanks to our new proprietary algorithm. For most types of shots, our Real Filter Emulations affect the image in a way that is almost indiscernible from the way the real physical diffusion filter affects the image -- albeit in terms of “feel & spirit” and not in exact, pixel-for-pixel emulation. No post production solution can authentically duplicate what a real physical diffusion filter does, at least until there are cameras that record in 14-bit color space with 40+ stops of dynamic range.

For some types of shots with heavy Variable Diffusion settings applied, like pans and handheld moving shots, I’m getting a “twinkling” or “pop off” effect around bright objects just as they are moving offscreen, similar to the way lens flares behave. Is there a way to minimize this “twinkling at frame edge” behavior?

Yes, there is a simple workaround that will disable this.

  1. In your comp (let’s call it “Main comp”), Control-click on your footage layer (let’s call it “Panning shot.mov”) and choose “Pre-compose...”.
  2. Then in the popup window, make sure “Leave all attributes in ‘Panning shot.mov” is selected and click “OK”.
  3. Open that new comp (let’s call it “New pre-comp”), and in the top menu bar click on "Composition" > "Composition Settings..."
  4. For the “Width” and “Height”, add two pixels to each dimension. For instance, if your comp is 1920 x 1080, change it to 1922 x 1082.


Now if you return to “Main comp” you will see that there is no “twinkling” or “pop off” behavior around bright objects as they move offscreen. The “twinkling at frame edge” behavior is a byproduct of our algorithm’s attempt to guess what lies around the frame edge in order to more realistically emulate how light is diffused by real glass filters in-camera, since they are affected by light that exists around the frame edge. By simply creating an empty one-pixel outer border (let’s call it a “moat”) in your layer, the algorithm’s “guessing” is confused and will then give you a very subtle change as bright objects move offscreen.

A couple things to note: The same behavior occurs as bright objects enter frame, but psychologically this does not feel as unintuitive as when they exit frame. That’s because we’re humans and we’re weird. The other thing to note is that the “subtle behavior" will only occur on frame edges that have a “moat” around them. For example, if the bright object enters screen left, and then exits screen right, and you prefer to retain Variable Diffusion’s original behavior for its entrance, but want to change its exit to be the “subtle behavior”, you can go into “New pre-comp” and change its width & height to 1921 x 1080 and move the layer “Panning shot.mov” so that there is only a “moat” on the right edge of the frame. Note to After Effects beginners: Just keep in mind that changing the comp size will sometimes reposition its layers in half pixel increments, which can add a half pixel's worth of softness. This is easily fixed in one of three ways: By looking at the layer’s position’s numeric value, then manually changing any decimals to whole numbers, or by zooming in to 200% and using the cursor keys to move it in half pixel increments, or the easiest method is changing the layer’s quality to “draft” which will disable subpixel sampling.

This “twinkling at frame edge” behavior is something we are currently working on improving, and such improvements might be included in a future version of Variable Diffusion (disclaimer: no promises though!). We hope this simple workaround can help in the meantime.