To Match Noise Or Grain Between Images - Adobe AFTER EFFECTS 7.0 Manual

To match noise or grain between images

The Match Grain effect matches the noise between two images. This is especially useful for compositing and in
bluescreen/greenscreen work. The Match Grain effect only adds noise and can't remove it, so if the destination is
already noisier than the source, an exact match is not possible. In this case, you can first use the Remove Grain effect
to clean up the destination and then apply the Match Grain effect to the result to get a perfect match.
The Match Grain effect uses noise sampling as its starting point. Basically, entire frames of new noise are synthesized
to match the noise samples. You can modify the noise in many ways before the effect is applied to the new image,
such as duplicate the noise from an image but make the noise larger and redder before applying the noise to another
image.
Note: The Match Grain effect samples the noise on the frame in the source layer that corresponds to the first frame in
the destination layer. If the source layer is not present at that frame, or if the noise samples contain transparent areas,
no noise is sampled or applied.
Computer graphics character (left) has no film grain (center), and using Match Grain effect (right)
Make sure that the source and the destination layers are in the same composition.
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Select the destination layer to which you want to add grain.
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Choose Effect > Noise & Grain > Match Grain.
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4 Choose a layer from the Noise Source Layer control in the Effect Controls panel to specify the source layer from
which you want to sample the grain. (The Noise Source Layer control lists only layers that are in the Timeline panel.)
The grain is automatically sampled and applied to the preview region on the destination layer. If you need an
automatic match, you can skip the remaining steps.
If there already is significant noise in the destination layer before choosing a noise source layer and this causes a
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grain mismatch, adjust the Compensate For Existing Noise slider to avoid grain build-up.
Do any of the following:
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•
To adjust the intensity and size of the applied grain and to introduce a blur, adjust the Tweaking controls.
•
To modify the color of the added noise, adjust the Color controls.
•
To determine how the color value of the generated noise combines with the color value of the underlying desti-
nation layer at each pixel, choose a Blending Mode in the Application controls group.
•
To define how much grain is added to each tonal area in your image and the midpoint, adjust the Shadows,
Midtones, Highlights and Midpoint values in the Application controls group.
If you want to change the effect view, choose any of the following from the Viewing Mode menu in the Effect
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Controls panel:
Shows the areas that have been sampled to extract the current noise model. Selecting the source layer
Noise Samples
causes it to appear in the Composition panel, with its noise sample squares displayed.
Shows the noise samples that have been automatically extracted from the destination image.
Compensation Samples
Displays the current settings of the applied effect in a 200 x 200 pixels area.
Preview
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