User Manual

Although the Additive/Subtractive option is often an either/or checkbox in other
software, the Trails node lets you blend between the Additive and Subtractive versions
of the compositing operation. This can be useful when dealing with problem edges
that are too bright or too dark.
For example, using Subtractive merging on a premultiplied image may result in darker
edges, whereas using Additive merging with a non-premultiplied image causes any
non-black area outside the foreground’s Alpha to be added to the result, thereby
lightening the edges. By blending between Additive and Subtractive, you can tweak
the edge brightness to be just right for your situation.
Alpha Gain
Alpha Gain linearly scales the Alpha channel values of the trailing objects in front. This
effectively reduces the amount that the trailing objects in the background are obscured, thus
brightening the overall result. When the Subtractive/Additive slider is set to Additive with Alpha
Gain set to 0.0, the foreground pixels are added to the background.
When the Subtractive/Additive slider is set to Subtractive, this controls the density of the
composite, similar to Blend.
Burn In
The Burn In control adjusts the amount of Alpha used to darken the objects that trail under
other objects, without affecting the amount of in-front objects added. At 0.0, the blending
behaves like a straight Alpha blend. At 1.0, the objects in the front are effectively added onto
the objects in the back (after Alpha multiplication if in Subtractive mode). This gives the effect of
the foreground objects brightening the objects in the back, as with Alpha Gain. In fact, for
Additive blends, increasing the Burn In gives an identical result to decreasing Alpha Gain.
Merge Under
When enabled, the current image is placed under the generated trail, rather than the usual,
over top operation. The layer order of the trailing elements is also reversed, making the last trail
the topmost layer.
Common Controls
Settings Tab
The Settings tab controls are common to all Effect nodes, so their descriptions can be found in
“The Common Controls” section at the end of this chapter.
TV [TV]
The TV node
TV Node Introduction
The TV node is a simple node designed to mimic some of the typical flaws seen in analog
television broadcasts and screens. This Fusion-specific node is mostly obsolete when using
DaVinci Resolve because of the more advanced Analog Damage ResolveFX.
Chapter – 88 Effect Nodes 1966