Difference node — Natron 2.5.0 documentation

# Difference node

This documentation is for version 1.0 of Difference (net.sf.openfx.DifferencePlugin).

## Description

Produce a rough matte from the difference of two input images.

A is the background without the subject (clean plate). B is the subject with the background. RGB is copied from B, the difference is output to alpha, after applying offset and gain.

See also: http://opticalenquiry.com/nuke/index.php?title=The_Keyer_Nodes#Difference and http://opticalenquiry.com/nuke/index.php?title=Keying_Tips

## Inputs

Input | Description | Optional
--- | --- | ---
B | The subject with the background. | No
A | The background without the subject (a clean plate). | No

## Controls

Parameter / script name | Type | Default | Function
--- | --- | --- | ---
Offset / `offset` | Double | 0 | Value subtracted to each pixel of the output
Gain / `gain` | Double | 1 | Multiply each pixel of the output by this value