Noise

Adds various types of seemingly random noise to the input image, all based on the Perlin noise function.

See also Grain, ScannedGrain, and F_ReGrain.

Inputs and Controls

Connection Type

Connection Name

Function

Input

unnamed

The image sequence to which noise is added.

mask

An optional image to use as a mask. By default, the noise 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

Noise Tab

output

output

rgba

The noise is rendered into these output channels.

If you set this to something other than none, you can use the checkboxes on the right to select individual channels.

premult

premult

none

Premultiply multiplies the chosen input channels with a mask representing the noise. For example, where there is no noise (the matte is black or empty), the input channels are set to black. Where the noise is opaque (the matte is white or full), the input channels keep their full value.

Note:  Selecting rgba premultiplies the alpha against itself (a*a). If you don’t want this to happen, set premult to rgb instead.

clip to

cliptype

format

Select how to restrict the output image:

no clip - use the entire image.

bbox - restrict the output image to the incoming bounding box.

format - restrict the output image to the incoming format area.

unionbboxandformat - restrict the output image to a combination of the incoming bounding box and format area.

intersectbboxandformat - restrict the output image to an intersection of the bounding box and incoming format area.

replace

replace

disabled

When enabled, existing channels are cleared to black before drawing into them. You might find replace useful, for instance, if you’re creating a mask in the alpha channel, but the incoming image already has an alpha channel which you want to throw away.

invert

invert

disabled

When enabled, inverts the new noise and non-noise areas.

opacity

opacity

1

Sets the noise opacity where 0 is equal to transparent, and 1 is equal to opaque.

mask

N/A

disabled

Enables the associated mask channel to the right. Disabling this checkbox is the same as setting the channel to none.

maskChannelInput

none

The channel to use as a mask. By default, the noise 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 noise is limited to the non-white areas of the mask.

type

type

fBm

Choose the type of noise to use:

fBm (fractional Brownian motion) - runs noise() octave times at different scales to get random numbers between -1 and +1 and adds them up.

turbulence - similar to fBm except it uses the absolute value of the noise function so the values it sums up are all between 0 and 1.

x/ysize

size

350

Sets the lowest possible noise frequency on the x and y axes. For example, low y values relative to x produces horizontal noise.

z

zoffset

0

Offsets the noise to create new patterns. This control must be animated to produce noise changes over time. For example, the expression frame/10 causes the noise to change completely over 10 frames.

octaves

octaves

10

Sets the number of Perlin noise functions to add to the noise frequency.

clip at Nyquist limit

nyquist

enabled

When enabled, limits the number of octaves so that the highest frequency is larger than one pixel.

Note:  You may need to disable this control if you’re animating the size of the noise, as changes can be visible.

lacunarity

lacunarity

2

Sets the amount by which octaves multiply noise frequency. Lower values produce smoother noise and higher values produce more granular noise.

gain

gain

0.5

Sets the amount by which octaves multiply noise amplitude.

gamma

gamma

0.5

Sets the gamma output for the noise.

Transform Tab

translate xy

translate

0, 0

Translates the noise along the x and y axes. You can also adjust translate values by dragging the transform handle in the Viewer.

rotate

rotate

0, 0

Rotates the noise around the center x y coordinates. You can adjust rotate values by dragging the transform handle in the Viewer.

scale

scaling

1

Scales the noise width and height around the center x y coordinates.

skew

skew

0

Skews the noise on the x and y axes.

center xy

center

N/A

Sets the center of rotation and scale on the x and y axes.

xrotate

xrotate

30

Rotation around the x axis in 3D noise space. Setting this to zero reveals artifacts in the Perlin noise generator.

yrotate

yrotate

30

Rotation around the y axis in 3D noise space. Setting this to zero reveals artifacts in the Perlin noise generator.

Color Tab

ramp

ramp

none

Selects whether to create a color gradient across the noise:

none - don’t create a color gradient.

linear - the ramp changes linearly from one color into another.

smooth0 - the ramp color gradually eases into the point 0 end. This means colors in the point 0 end are spread wider than colors in the point 1 end.

smooth1 - the ramp color eases into the point 1 end. This means colors in the point 1 end are spread wider than colors in the point 0 end.

smooth - the ramp color gradually eases into both ends. This means colors in the point 0 and point 1 ends are spread wider than colors in the center of the ramp.

color

color

1

Sets a color for the noise.

If ramp is set to anything other than none, this is the color for the ramp at the point 1 end (by default, the top end).

point 1

p1

100, 400

Sets the position of point 1. This allows you to adjust the spread and angle of the ramp.

This control is only available if ramp is set to anything other than none.

color 0

color0

0

Sets the color for the ramp at the point 0 end (by default, the bottom end).

This control is only available if ramp is set to anything other than none.

point 0

p0

100, 100

Sets the position of point 0. This allows you to adjust the spread and angle of the ramp.

This control is only available if ramp is set to anything other than none.