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# Using Blend Nodes

Blend nodes include the Colour Blend (CBlend) and Matte Blend (MBlend) nodes.

A blend node is essentially a container that you can use to create a “mini-composite” at different parts of the pipeline. CBlend and MBlend nodes each comprise one or more layers that include the components needed for a composite: a front, matte, and back component. These components are referred to as pipes, and they may contain as many nodes as needed to create the desired image.

The two pipes of blend nodes provide extra functionality compared to branches in the pipeline:

- You can apply the processes to a selected region of the image. You use the lower of the two pipes to define the area on the image where you want to apply the processes used in the upper pipe. For example, you could add a garbage mask node to the lower branch and create a matte. The processes in the upper pipe are only applied to the foreground subject of the matte. If there are no nodes in the lower pipe, the processes in the upper pipe are applied to the entire image.
- You can blend the two pipes in various ways.
- You can use multiple layers. The two pipes together constitute a layer. You can add one to three additional layers to blend nodes.

(a) The Front and Matte pipes of the blend node constitute one layer.

The back component is not represented visually as it is applied automatically to the composite.

Nodes on the pipes are processed sequentially, with a single input and single output to and from each node. Therefore, you cannot add multiple input nodes that require several clips (such as the Logic Op node) to pipes. However, some multiple input nodes can operate with only one input source, for example, the Gmask, Colour Correct, and Regrain nodes. If you add one of these node types to a blend node pipe, it is “converted” to a single-input node.

You can animate the curves in the MatteCurves, CBlend, MBlend, Colour Curves, or Result nodes.

Use the CBlend node to create a composite that results in a colour image. Use the MBlend node to create a composite that results in a matte.

#### Topics in this section

- Colour Blend Node
- Matte Blend Node
- Adding a Matte to a Blend Node
- Blending the Front and Back Images of a Layer
- Using Several Layers in a Blend Node
- Bypassing Pipes