Dissolve Node

The Dissolve node is typically used to mix two images together, providing a gradual transition between two clips. A Background/Foreground slider controls the mix between the foreground and background images. Dissolves are commonly used to transition between one clip and another and are a very common effect in editing. However, you can also use the extreme left and right positions of the Background/Foreground slider to switch between inputs. Unlike other nodes in Fusion, the Dissolve node does not require you to connect an image to the background but lets you output either the background or foreground according to the setting of the Background/Foreground slider.

This quality makes it possible for you use the Dissolve node as an automatic layer switching tool when connected to background and foreground clips with different durations. Simply connect each clip to the background and foreground inputs, respectively, and set the Background/Foreground slider to the input of shorter duration, to determine which is “on top.” After the last frame of that clip has ended, the Dissolve node automatically switches to the clip that’s connected to the other input.

Besides the default dissolve, the Gradient Wipe setting of the Operation menu allows you to create arbitrary animated dissolve patterns based on the luminance of an image connected to the optional Gradient Wipe input. You can use this capability with images of geometric shapes or gradients of different kinds, movie clips of fire, water ripples, or rain, the Fast Noise node, or even particle systems you create within the Fusion page to create a variety of unique and creative transitions. Soft-edged effect masks may also be used to add to the possible effects.

Ultimately, animating the Background/Foreground control allows you to control the transition that’s being used to switch from the foreground input to the background, or vice versa.

Dissolve Node Inputs

The Dissolve node provides three image inputs, all of which are optional:

• Background: The first of two images you want to switch between or mix. Unlike most other nodes, it is unnecessary to connect the background input before connecting the foreground input.
• Foreground: The second of two images you want to switch between or mix. The Dissolve node works best when both foreground and background inputs are connected to images with the same resolution.
• Gradient Map: (Optional) The Gradient Map is required only when Gradient Wipe is selected.

Dissolve Node Setup

Dissolve nodes are typically connected in the following way, with two input images connected to the background and foreground inputs, and the output connected to the next node in the composition.

Resolution Handling

It is recommended to make sure that all images connected to the foreground, background, and gradient map inputs of the Dissolve node have the same resolution and the same pixel aspect. This is not required, however. But, the result if you mix resolutions depends on how you set the Background/ Foreground slider

• If the input images are different sizes, but the Foreground/Background slider is set to full Foreground (all the way to the right) or full Background (all the way to the left), then the output resolution will be identical to the image resolution of the corresponding node input.
• If input images of different sizes are mixed by setting the Background/Foreground slider somewhere between, the output resolution will be set to the larger of the two input resolutions to make sure there’s enough room to contain both images. In this case, you may experience undesirable resolution changes when the slider moves from full foreground or background to somewhere in between. For example, if you try to dissolve between a 4K image (connected to the background) and an 8K image (connected to the foreground), the output of the Dissolve node will be 4K when the slider is set to full Background, but will suddenly jump to 8K when set to full Foreground or when mixed somewhere between the foreground and background.

Dissolve Node Controls Tab

These are the main controls that govern the Dissolve node’s behavior.

• Operation Pop-Up: The Operation menu contains one of seven different methods for mixing the Foreground and Background inputs. The two images are mixed using the value of the Background/ Foreground slider to determine the percentage each image contributes.
  • Dissolve: The standard Dissolve mode is the equivalent of a cross dissolve: one clip fades out as another clip fades in.
  • Additive Dissolve: Similar in look to a standard film dissolve, an Additive dissolve adds the second clip and then fades out the first one.
  • Erode: The Erode method transitions between the two images by growing the darkest areas of the background image to reveal the foreground image. The effect appears similar to a filmstrip burning out.
  • Random Dissolve: A randomly generated dot pattern is used to perform the mix of the images.
  • Random Noise Dissolve: A moving random dot pattern is used to perform the mix of the images.
  • Gradient Wipe: The dissolve is controlled by the luminance values of the image in the Gradient Map input. The edges of this dissolve can be softened. The density and the color of the border can be adjusted independently.
  • SMPTE Wipe: The SMPTE wipe is similar to the basic effect wipes found on many video effects switchers. There is a horizontal wipe and a vertical wipe provided. The wipes can have soft edges and borders added. The density and the color of the border can be adjusted independently.
• Background/Foreground Slider: Defaults to Foreground. This control determines whether the output is the background image, the foreground image, or a mix between the two. The type of mix is determined by the Operation control. If one of the input images is not currently available, the other one will be output despite the setting of this slider.

Gradient/SMPTE Wipe Controls

The following controls appear only when Gradient Wipe or SMPTE Wipe are selected.

• Wipe Style: (SMPTE Wipe only) This drop-down list allows the selection of two wipe styles: Horizontal – Left to Right and Vertical – Top to Bottom. The direction of the wipes can be reversed by using the Invert Wipe checkbox.
• Invert Wipe: (SMPTE Wipe only) When checked, the direction of the wipe will be reversed.
• Softness: Use this control to soften the edge of the transition.
• Border: Select the Border to enable coloring of the transition’s edge and to reveal the associated controls. The effect is to create a border around the transition edge.
• Border Softness: (Appears only when Border is turned on) The Border Softness slider controls the width and density of the border. Higher values will create a denser border, and lower values will create a thinner one.
• Border Color: (Appears only when Border is turned on) Use Border Color to select the color used in the border

Dissolve Node Settings Tab

The Settings tab in the Inspector is also duplicated in both the Dissolve and Merge nodes. These common controls are described in detail HERE.