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Grain

The Grain node lets you add synthetic grain (rather than grain derived from actual film stock) to an image. This helps you ensure that all of the elements in your composite, including those which were digitally generated, look like they were shot on the same film stock.

The presets dropdown menu includes predefined types of grain, such as Kodak 5248 and Kodak 5218. These are the correct size for 2K scans.

You can also adjust the Grain node’s controls to match a sample piece of grain:

Find a sample with a rather constant background.

Blur the sample to remove the grain.

Connect the blurred sample to the Grain node’s input.

In the Viewer, wipe between the Grain node and the original sample image, and adjust the Grain node’s controls to match the grain. It helps to view and match each of the red, green, and blue channels separately.

Inputs and Controls

Connection Type	Connection Name	Function
Input	1	The image sequence to receive the grain.

Control (UI)	Knob (Scripting)	Default Value	Function
User Tab
seed	seed	134	A different grain pattern is produced for each frame. Change this number to get a different initial pattern, for instance if you are using multiple Grain nodes. If you require an identical grain plate for every frame, enter -frame in this field.
presets	presets	N/A	Choose the film stock you want to match: • Kodak 5248 • Kodak 5279 • Kodak FX214 • Kodak GT5274 • Kodak 5217 • Kodak 5218 • other - changes the label on the node to other. This has no effect on the grain applied.
Size
red	red_size	3.3	Shrinks or enlarges the grain granules in the red channel.
green	green_size	2.9	Shrinks or enlarges the grain granules in the green channel.
blue	blue_size	2.5	Shrinks or enlarges the grain granules in the blue channel.
Irregularity
red	red_i	0.6	Increases or decreases the random quality of the grain in the red channel.
green	green_i	0.6	Increases or decreases the random quality of the grain in the green channel.
blue	blue_i	0.6	Increases or decreases the random quality of the grain in the blue channel.
Intensity
red	red_m	0.416	Increases or decreases the contrast of the grain in the red channel against the original image.
green	green_m	0.46	Increases or decreases the contrast of the grain in the green channel against the original image.
blue	blue_m	0.85	Increases or decreases the contrast of the grain in the blue channel against the original image.
black	black	0	The base amount of grain to add at the black point.
minimum rgb	minimum	0, 0, 0	The minimum output rgb values. If the grain calculation results in pixel values lower than these, these values are used instead.
Mask
Apply only through alpha	maskgrain	enabled	When enabled, grain is limited to the non-black areas of the image’s alpha channel. This can be useful when you want to apply grain to premultiplied CG images without contaminating the background black. When disabled, grain is applied to the entire image.
Invert alpha	invert_mask	disabled	Inverts the use of the alpha channel, so that when Apply only through alpha is enabled, grain is limited to the non-white areas of the alpha.