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Posterize

Posterize reduces the color resolution of an image. This creates abrupt changes from one tone to another, producing a dramatic graphic effect.

Inputs and Controls

Connection Type	Connection Name	Function
Input	unnamed	The image sequence to posterize.
mask	An optional image to use as a mask. By default, the posterize effect is limited to the non-black areas of the mask. At first, the mask input appears as triangle on the right side of the node, but when you drag it, it turns into an arrow labeled mask. If you cannot see the mask input, ensure that the mask control is disabled or set to none.

Connection Type

Connection Name

Function

Input

unnamed

The image sequence to posterize.

mask

An optional image to use as a mask. By default, the posterize effect is limited to the non-black areas of the mask.

At first, the mask input appears as triangle on the right side of the node, but when you drag it, it turns into an arrow labeled mask. If you cannot see the mask input, ensure that the mask control is disabled or set to none.

Control (UI)	Knob (Scripting)	Default Value	Function
Posterize Tab
channels	channels	all	The posterize effect is only applied to these channels. If you set this to something other than all or none, you can use the checkboxes on the right to select individual channels.
Colors	Colors	16	The bit depth to use. For example, setting this control to 8 independently limits each affected channel to 256 colors.
mask	N/A	disabled	Enables the associated mask channel to the right. Disabling this checkbox is the same as setting the channel to none.
mask	maskChannelInput	none	The channel to use as a mask. By default, the posterize effect is limited to the non-black areas of this channel.
inject	inject	disabled	Copies the mask input to the predefined mask.a channel. Injecting the mask allows you to use the same mask further downstream.
invert	invert_mask	disabled	Inverts the use of the mask channel so that the posterize effect is limited to the non-white areas of the mask.
fringe	fringe	disabled	Blurs the edges of the mask.
(un)premult by	N/A	disabled	Enables the associated channel to the right. Disabling this checkbox is the same as setting the channel to none.
(un)premult by	unpremult	none	The image is divided by this channel before being processed, and multiplied again afterwards. If you are using premultiplied input images, you may want to check (un)premult by and select rgba.alpha here. This will simulate doing the posterization before the premultiplication was done. It is the same as adding an Unpremult node before this node and a Premult node after, but allows you to work faster if you’re only using one color correct node. If you are using unpremultiplied input images, you should leave this set to none.
invert	invert_unpremult	disabled	Inverts the use of the (un)premultiply channel.
mix	mix	1	Dissolves between the original image at 0 and the full posterize effect at 1.