Noise and Grain effects

Almost every digital image captured from the real world contains grain or visual noise caused by the recording, encoding, scanning, or reproduction processes and by the equipment used to create the image. Examples include the faint static of analog video, compression artifacts from digital cameras, halftone patterns from scanned prints, CCD noise from digital image sensors, and the characteristic speckle pattern of chemical photography, known as film grain.

Noise isn’t necessarily bad; it’s often added to images to create a mood or tie elements together, such as adding film grain to a computer-generated object to integrate it into a photographed scene. However, noise can be unwanted for aesthetic reasons. Archival footage or high-speed photography may appear unpleasantly grainy; digital compression artifacts or halftone patterns may mar an image; or noise may interfere with technical processes such as bluescreen compositing.

Technical reasons also exist for reducing noise. For example, compression algorithms usually achieve smaller file sizes if the input material is less noisy, so noise reduction is a valuable preprocessing step for work such as DVD creation and video streaming.

The Add Grain, Match Grain, and Remove Grain effects allow you to manipulate grain that appears more or less evenly over an entire image. Grain effects can’t correct image problems that affect only a few pixels, such as dust, salt and pepper noise, or analog video dropouts.

The Add Grain effect generates new grain from nothing; it doesn’t take samples from existing grain. Instead, parameters and presets for different types of film can be used to synthesize different types of grain.

The Remove Grain and Match Grain effects use a two-step process to manipulate grain without affecting the edges, sharpness, or highlights of an image. First, the grain is sampled, either automatically or manually; second, the grain is analyzed and portrayed by a mathematical model, which the effect uses to add, remove, or match the grain.

Apply a grain effect

Each grain effect is applied with default settings and is displayed in Preview viewing mode, which has a preview region framed by a white border and centered on the image. The preview region displays the results of the grain effect on a portion of your image, for speed and comparison purposes. The grain effects are almost fully automatic but also offer many controls to achieve precise results. You can also selectively apply the grain effects to portions of your image using the extensive Blend With Original features provided with each effect.

Apply a grain effect to a selected area

The Blend With Original controls group lets you precisely apply a grain effect to a particular area of an image by masking and matting the desired area. You can choose between two selection techniques or use a combination of both:

Color Matching

Excludes any area of the image that matches a selected color. By inverting the matte, you can also selectively process such an area.

Masking Layer

Uses any layer in the current composition as a mask to selectively process or exclude an area of the current layer or track.

When any grain effect is first applied, the Amount value of the Blend With Original controls group is set to 0%; this value determines the percentage of blending between the original image and the processed version. At 0%, no blending occurs and the selected effect is applied to the entire image at full strength; at 100%, white areas of the blending matte are unchanged from the original image.

Any mask or matte works in a similar way: The white pixels in it exclude that area of the original image from processing by the grain effect; the black pixels process normally. At 100% Amount, the white areas fully blend with the original so that they are completely excluded from the processing. This behavior remains true when the match is inverted. Regardless of the Amount value, the black areas of the matte or mask are always processed. The Amount slider affects only the areas under the white pixels in the matte or mask. It affects only how each grain effect treats the white areas of the matte or mask.

Generate a color-matching matte

When a grain effect is first applied, a neutral gray color is used to generate a default color-matching matte, so that in most images a visible matte appears. The Color Matching group of controls uses color matching to precisely define a matte. The matte isolates portions of the image where the layer that uses the grain effect is blended with the input.

Generate a layer matte

In some cases, you may want to use a different layer or track as a mask for the layer that uses a grain effect. This type of mask allows unlimited control over exactly which parts of an image are modified and by how much.

Change the preview region

You can use the Preview Region controls group to change the position or the size of the preview region for a grain effect.

Because adding or removing grain can affect sharpness of detail, you may want to preview an area of fine detail, such as a human face or some text. When you remove grain with the Remove Grain effect, a best practice is to preview an area where the grain is most clearly visible or most objectionable, such as a large expanse of solid color.

You’ll achieve the best results by experimenting, applying small increments to each of several controls in the Effect Controls panel, and viewing the results in the Composition panel after every adjustment.

Work with noise samples in Grain effects

Noise sampling is the first and most important step in removing noise from an image or in matching the noise of one image in another image. Normally, this process is entirely automatic. For fine control, you can switch to Manual mode and adjust the samples using the Sampling controls group in the Effect Controls panel.

A noise sample should be a solid block of uniform color that clearly displays the noise pattern present in the image. The objective is to extract samples of pure noise, without any image features that the algorithm could misconstrue as grain. For example, extract samples from a piece of sky, a background wall, or an area of fleshtone. All samples should be selected from the normal range of the film, DV, or video stock. Avoid underexposed or overexposed areas lacking in information, especially areas where pixel values have been clipped to pure black or white. Within this normal exposure range, it’s best to select samples with various RGB values and colors—for example, one sample from a bright area, one from a dark area, and one from an area with midtones.

The number of samples in automatic mode is high to ensure that the algorithm has enough good noise data, even if finding good samples in a particular image is difficult. In addition, automatic mode may override the number of samples you’ve set if the effect can’t find enough good samples. You can vary the size of the samples in either automatic or manual mode; however, increasing sample size doesn’t guarantee better results, especially if the resulting samples include more substantial variations in RGB values. Sample size should be reduced if a particular image doesn’t contain sufficiently large areas of constant color values. Conversely, increasing the sample size may give better results if the image contains large featureless areas.

Manually reposition noise samples

Automatic grain or sample selection generally gives acceptable results for the Match Grain or Remove Grain effect, but you can choose to manually position and resize each sample or change the sample number. For example, you may want to reposition samples if the automatic sampling selected a uniform area that is underexposed or overexposed and that lacks information about grain structure.

Noise samples for the Match Grain and Remove Grain effects are always extracted from the source layer without regarding any effects or masks already applied to the layer; this method results in more accurate sampling. If you want the samples to include the existing effects, precompose or pre-render the source layer with the effects and then apply the grain effect to the resulting source layer.

Avoid sample areas with the following characteristics: sharp edges, color gradients, highlights, textures such as grass or water ripples, fine detail such as hair or tree leaves, and overexposed or underexposed areas lacking in information.

Change the sampling source frame

By default, the Remove Grain and Match Grain effects take noise samples from the first frame of the layer, but you can choose to sample the noise from a different frame. Changing the frame may be useful if large lighting or exposure variations occur between frames within the layer.

Change the noise sample box color

You can set the viewing mode for the Remove Grain or Match Grain effect to Noise Samples to see the areas sampled by the effect. Sampled areas are automatically framed with a white outline. If you prefer, you can change the color of these noise sample boxes.

Working with added or matched grain

The Add Grain effect creates new grain or noise in an image by building the grain from nothing or by basing the properties of the grain on presets. The Match Grain effect also creates new grain in an image but by matching the grain in a different image. Both effects share several controls in the Effect Controls panel that let you control the color, tonal range, blending mode, and animation properties of the grain.

Adjusting the tones of added or matched grain

The precise grain pattern present in any frame of film isn’t uniform throughout the frame but may depend on the tonal values of the content at each pixel. For example, in chemical film grain, the sizes of the silver halide crystals vary with the exposure level.

The Add Grain and Match Grain effects let you reproduce these subtle changes in grain patterns across areas of an image by using the Shadows, Midtones, Highlights, and Midpoint controls in the Application controls group. These controls let you define how much grain is added to each tonal area and also to each channel in the image. For example, you can add more grain to overexposed areas of the blue channel to give an image of sky a grainier look.

You can use the Application controls group for the Add Grain or Match Grain effect to do the following:

• To define how much grain is added to each tonal area in an image, adjust the Shadows, Midtones, and Highlights values.

• To define the midpoint of the tonal range of the image for grain application purposes, adjust the Midpoint slider. By default, this slider is centered at 0.5, which represents the middle of the range of pixel values—127 for 8-bpc images and 16384 for 16-bpc images.

• For even finer control, use the Channel Balance controls to adjust the grain in the shadow, midtone, and highlight areas independently for each channel.

Animating added or matched grain

By default, the grain or noise generated by the Add Grain and Match Grain effects moves at the same speed as the source material to accurately simulate realistic noise. Slowing down the noise processes may be useful for aesthetic effect or to keep the added noise from buzzing and drawing attention to itself. These effects have an internal randomizer that changes the positions of the noise pixels between frames. But you can also change the appearance of the noise between layers on the same frame while keeping every other parameter constant.

You can use the Animation controls group for the Add Grain or Match Grain effect to do the following:

• To specify the frame rate of the added grain, as a multiple of the destination frame rate, adjust the Animation Speed value in the Animation controls group in the Effect Controls panel. At higher Animation Speed values, the lifespan of the grains is lower. At the default value of 1, the grain moves at the same rate as the frames. At lower values, the grain changes more slowly, which can be useful for giving the appearance of film grain. At zero, the grain is stationary over time.

• To use interpolation to create smooth transitions between the generated noise frames, select Animate Smoothly. This control matters only if Animation Speed is less than 1.

• To change the appearance of the noise between layers on the same frame, adjust the Random Seed value. Each Random Seed value represents one of 100 possible variations in the appearance; changing the value doesn’t make the results more or less random.

Blending and adjusting the color of added or matched grain

You can adjust the color, saturation, and blending behavior of the grain generated by the Add Grain or Match Grain effect.

Several factors can affect the apparent color of the grain that these effects generate, including the following:

• The color value of the underlying pixel in the source image.

• The Saturation value of the noise.

• The Tint Color and Tint Amount values, if you have modified these settings from the defaults.

• The Blending Mode value in the Application controls group.

• The amount of noise applied, if any, to each channel individually using the Channel Intensities controls group.

Using the Color controls group in the Effect Controls panel, you can adjust any of the following:

Gives the added noise a single tint. By default, the tones are black and white, but you can change the Tint Color to make it a gradient of any color. (The Saturation and Channel Intensities controls aren’t available if Monochromatic is selected.)

Controls the depth and intensity of the color shift.

Controls the color the added noise shifts toward.

Controls the amount and vividness of the color.

The Blending Mode in the Application controls determines how the color value of the generated noise combines with the color value of the underlying source layer at each pixel:

Makes the generated grain appear embedded in the image. This mode affects darker colors more than lighter ones, just as the grain in a film negative appears.

Multiplies the color values of the noise and the source. However, the result may be either lighter or darker than the original, because the noise may have either a positive or negative value.

Combines the color values of the pixel in the source with the noise. However, the result isn’t always lighter than the original because the noise created by grain effects can have either a positive or negative value.

Multiplies the inverse brightness values of the noise and the source. The effect is like printing from a multiple exposure on a negative. The result is always brighter than the original.

Combines the behavior of Film and Multiply: Both shadows and highlights get less grain, while midtones get a full application of grain.

Add Grain effect

The Add Grain effect generates new noise from nothing and does not take samples from existing noise. Instead, parameters and presets for different types of film can be used to synthesize many different types of noise or grain. You can modify virtually every characteristic of this noise, control its color, apply it to the image in several ways, even animate it or apply it selectively to only a part of your image.

This effect works with 8-bpc and 16-bpc color.

The distribution of the added noise over the color channels does affect the overall color of the resulting image. With a dark background, the noise tends to add to the image visually, so a red tint or more noise in the red channel gives a reddish hue to the image. With a bright background, the noise tends to subtract from the image visually, so a red tint or more noise in the red channel gives a cyan color. The result also depends on the Blending Mode control in the Application controls group.

You can use the controls for the Add Grain effect to do the following:

• To reproduce the grain of a particular film or photographic stock, choose the film type from the Preset menu for the Add Grain effect in the Effect Controls panel.

• To adjust the intensity and size of the applied grain and introduce a blur, adjust the Tweaking controls group for the Add Grain effect in the Effect Controls panel.

• To modify the color of the added noise, adjust the Color controls.

• To define how the color value of the generated noise combines with the color value of the underlying destination 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.

• To animate the added grain, adjust the properties in the Animation controls group.

• To apply the effect to the entire image, choose Final Output from the Viewing Mode menu.

Tweaking controls for Grain effects

The Match Grain and Add Grain effects share a group of Tweaking controls. You can use these controls to modify the intensity and size of the noise and to introduce a blur, all of which can be done across the three channels or individually for each channel. You can also change the aspect ratio of the applied grain.

Adjust any of the following controls in the Tweaking controls group:

Controls the amount of variation in brightness and color strength between pixels in the generated noise, which determines the visibility of the noise. Increasing the value does not change the position or size of each grain but makes the grain appear to pop more; lower values give a more subtle muted appearance.

Controls the contrast between pixels in the generated noise separately for each channel. For example, you may want to add more grain to the blue channel to emulate film.

Adjusts the size of the generated grain in pixels.

Adjusts the size of the generated grain in pixels independently for each channel.

Sets the amount of softness in the grain.

Controls the ratio of the width of the generated grain over a constant height of 1; this setting is useful for emulating the effect of anamorphic lenses or for aesthetic effects. A value higher than 1 stretches the grain horizontally; values smaller than 1 squash it horizontally.

Dust & Scratches effect

The Dust & Scratches effect reduces noise and defects by changing dissimilar pixels within a specified radius to be more like their neighboring pixels. To achieve a balance between sharpness of the image and hiding defects, try various combinations of Radius and Threshold settings.

This effect works with 8-bpc and 16-bpc color.

How far the effect searches for differences among pixels. High values make the image blurry. Use the smallest value that eliminates the defects.

How different pixels can be from their neighbors without being changed by the effect. Use the highest value that eliminates the defects.

Fractal Noise effect

The Fractal Noise effect uses Perlin noise to create grayscale noise that you can use for organic-looking backgrounds, displacement maps, and textures, or to simulate things like clouds, fire, lava, steam, flowing water, or vapor.

This effect works with 8-bpc, 16-bpc, and 32-bpc color.

The Evolution controls create subtle changes in the shape of the fractal noise. Animating these controls results in smooth changes of the noise over time, creating results that resemble, for example, passing clouds or flowing water.

Stu Maschwitz provides an example project on his ProLost blog that uses the Fractal Noise effect to create the corona of the Sun.

The Turbulent Noise effect is essentially a modern, higher-performance implementation of the Fractal Noise effect. The Turbulent Noise effect takes less time to render, and it’s easier to use for creating smooth animations. The Turbulent Noise effect also more accurately models turbulent systems, with smaller noise features moving more quickly than larger noise features. The primary reason to use the Fractal Noise effect instead of the Turbulent Noise effect is for the creation of looping animations, since the Turbulent Noise effect doesn’t have Cycle controls.

Controls

The fractal noise is created by generating a grid of random numbers for each noise layer. The Complexity setting specifies the number of noise layers. The Fractal Type setting determines the characteristics of this grid.

The type of interpolation to use between the random values in the noise grid.

Inverts the noise. Black areas become white, and white areas become black.

The default value is 100. Higher values create larger, more sharply defined areas of black and white in the noise, generally revealing less subtle detail. Lower values result in more areas of gray, softening or muting the noise.

Remaps color values that fall outside the range of 0–1.0, using one of the following options:

Remaps values so that any value above 1.0 is displayed as pure white, and any value below 0 is displayed as pure black. The Contrast value influences how much of the image falls outside this range. Higher values result in a mostly black and/or white image with less gray area. Therefore, higher contrast settings display less subtle detail. When used as a luma matte, the layer has sharper, better-defined areas of transparency.

Remaps values on an infinite curve so that all values stay in the range. This option reduces contrast and makes noise appear gray with few areas of pure black or pure white. When used as a luma matte, the layer contains subtle areas of transparency.

Remaps triangularly, so that values above 1.0 or below 0 fall back into the range. This option reveals subtle detail when Contrast is set above 100. When used as a luma matte, the layer reveals more detailed textured areas of transparency.

No remapping is performed. Values outside the range of 0-1.0 are preserved.

Settings to rotate, scale, and position the noise layers. The layers appear as if they are at different depths if you select Perspective Offset.

The number of noise layers that are combined (according to the Sub Settings) to create the fractal noise. Increasing this number increases the apparent depth and amount of detail in the noise.

The fractal noise is generated by combining layers of noise. The Sub Settings control how this combination occurs and how the properties of the noise layers are offset from one another. Scaling successive layers down creates finer details.

How much influence each successive layer has on the combined noise. At 100%, all iterations have the same amount of influence. At 50%, each iteration has half as much influence as the previous iteration. A value of 0% makes the effect appear exactly as if Complexity is 1.

The scale percentage, angle, and position of a noise layer relative to the previous noise layer.

Calculates each noise layer from the same point as the previous layer. This setting can result in the appearance of duplicated noise layers stacked on top of each other.

Uses progressive revolutions that continue to change the image with each added revolution. This method is unlike typical revolutions that refer to a setting on the dial control for which the result is the same for every multiple of 360°. For Evolution, the appearance at 0° is different from the appearance at 1 revolution, which is different from the appearance at 2 revolutions, and so on. To return the Evolution setting to its original state (for example, to create a seamless loop), use the Cycle Evolution option.

You can specify how much the noise evolves over a period of time by animating Evolution. The more revolutions within a given amount of time, the more rapidly the noise changes. Large changes in the Evolution value over a short period of time may result in flashing.

To create a seamless loop, use Cycle Evolution, and set Evolution keyframes at full revolutions with no degrees—partially completed revolutions may interrupt the loop.

Options for Evolution.

Creates a cycle of Evolution that loops over the set amount of time. This option forces the Evolution state to return to its starting point, creating a smooth progressive cycle, a nonrepeating cycle, or a loop segment.

To ensure that a cycle completes full revolutions, choose a Cycle value that either matches or is evenly divisible by the number of revolutions set for Evolution.

Specifies the number of revolutions that the noise cycles through before it repeats. The amount of time between Evolution keyframes determines the speed of these Evolution cycles. This option affects only the evolution of the noise, not Transform or other controls. For example, if you view two identical states of noise with different Size or Offset settings, they don’t appear the same.

Sets a random value from which to generate the noise. Animating the Random Seed property results in flashing from one set of noise to another (within that fractal type), which is usually not the result that you want. For smooth animation of noise, animate the Evolution property.

Opacity of the noise.

The blending operation between the fractal noise and the original image. These blending modes are identical to the ones in the Modes column in the Timeline panel, with the following exceptions:

Renders the fractal noise only and does not composite on the original layer.

Renders the fractal noise as hue values instead of grayscale. The Saturation and Lightness of the original layer are maintained. If the original layer is grayscale, nothing happens.

Renders the fractal noise as saturation values instead of grayscale. The Hue and Lightness of the original layer are maintained. If the original layer is grayscale, nothing happens.

Create a seamless loop using Fractal Noise

Match Grain effect

The Match Grain effect matches the noise between two images. This effect 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 duplicating the noise from an image but making the noise larger and redder before applying the noise to another image.

The Match Grain effect shares some controls with the Add Grain effect. (See Add Grain effect.)

This effect works with 8-bpc and 16-bpc color.

Match noise or grain between images

Compensate for existing noise when matching noise

If you’re trying to match the grain between images with the Match Grain effect, and your destination layer already has its own visible grain, a grain mismatch or grain build-up may occur. To prevent these problems, the Compensate For Existing Noise control extracts a noise model from both the source and the destination and then modifies the noise from the source to account for the noise already present in the destination, before applying it to the destination.

To use this control automatically, set the Compensate For Existing Noise slider to 100%. You can then view the noise samples in the destination layer by choosing Compensation Samples in the Viewing Mode menu. You can also reposition the samples in the destination image by setting Sampling Mode to Manual, which makes the Compensation Sample Points available for manual repositioning.

Median effect

The Median effect replaces each pixel with a pixel that has the median color value of neighboring pixels with the specified Radius. At low Radius values, this effect is useful for reducing some types of noise. At higher Radius values, this effect gives an image a painterly appearance.

This effect works with 8-bpc and 16-bpc color.

Noise effect

The Noise effect randomly changes pixel values throughout the image.

This effect works with 8-bpc, 16-bpc, and 32-bpc color.

The amount of noise to add.

Use Color Noise adds random values to the red, green, and blue channels individually. Otherwise, the same random value is added to all channels for each pixel.

Clips color channel values. Deselecting this option causes more apparent noise. This control does not work in a 32-bpc project.

Noise Alpha effect

The Noise Alpha effect adds noise to the alpha channel.

This effect works with 8-bpc color.

The type of noise. Unique Random creates equal amounts of black and white noise. Squared Random creates high-contrast noise. Uniform Animation creates animated noise, and Squared Animation creates animated high-contrast noise.

The magnitude of the noise.

How to apply the noise to the alpha channel:

Produces equal amounts of noise in the transparent and opaque areas of the clip.

Produces noise in the opaque areas only.

Increases the amount of noise proportionate to the level of opacity and produces no noise in 100% transparent areas.

Produces noise only in partially transparent areas, such as the edge of the alpha channel.

How the effect remaps values that fall outside the grayscale range of 0-255:

Values above 255 are mapped to 255. Values below 0 are mapped to 0.

Values above 255 or below 0 are reflected back into the 0-255 range. For example, a value of 258 (255+3) is reflected to 252 (255-3), and a value of ‑3 is reflected to 3.

Values above 255 and below 0 are wrapped back around into the 0-255 range. For example, a value of 258 wraps around to 2, a value of 256 wraps around to 0, and a value of ‑3 wraps around to 253.

An input value to the random number generator for the noise. This control is active only if you choose Uniform Random or Squared Random.

Specifies the placement of noise. This control is active only if you choose Uniform Animation or Squared Animation.

How noise is animated.

Alter the timing of the Noise Phase keyframes to adjust the speed of the Noise Phase cycles.

Produces a cycle of noise that plays through once in the specified amount of time.

Specifies the numbers of revolutions of the Noise Phase that the noise cycles through before it repeats (available only when Cycle Noise is selected).

Noise HLS effect and Noise HLS Auto effect

The Noise HLS and Noise HLS Auto effects add noise to the hue, lightness, and saturation components of an image. The noise generated by the Noise HLS Auto effect is automatically animated noise; you choose the speed of the animation. To animate the Noise HLS effect, use keyframes or expressions. Controls for these effects are the same except for the Noise Phase or Noise Animation Speed control, which controls noise animation.

These effects work with 8-bpc color.

The type of noise. Uniform produces uniform noise. Squared creates high-contrast noise. Grain produces grainlike noise similar to film grain.

The amount of noise added to hue values.

The amount of noise added to lightness values.

The amount of noise added to saturation values.

This control is active only for the Grain type of noise.

An input value to the random number generator for the noise. When you set keyframes for Noise Phase, the effect cycles through the phases to create animated noise. Greater value differences between keyframes increase the speed of the noise animation.

The speed of the noise animation. To accelerate or decelerate the noise animation, animate this property.

Remove Grain effect

To remove grain or visual noise, use the Remove Grain effect. This effect uses sophisticated signal processing and statistical estimation techniques in an attempt to restore the image to how it would look without the grain or noise. While many techniques, such as applying a mild Gaussian Blur effect or the Median effect, reduce the visibility of noise in an image, the tradeoff is an unavoidable loss of sharpness and highlights. The Remove Grain effect, in contrast, differentiates fine image detail from grain and noise and preserves the image detail as much as possible.

The Remove Grain effect provides several options to precisely balance the reduction in noise and the amount of sharpness retained in the image. Additionally, the Remove Grain effect can analyze the differences between frames to further improve noise reduction and sharpness; since this process operates over time, it is called temporal filtering.

The Temporal Filtering controls of the Remove Grain effect use a statistical algorithm to blend the current frame with previous and next frames. These controls are especially effective in removing compression artifacts from DV or video footage.

To properly evaluate the results of this filter, the result must be viewed in real time, either with a review or by viewing a movie rendered to a file.

This effect works with 8-bpc and 16-bpc color.

Remove noise or grain from an image

Add temporal filtering to a layer

Sharpen an image with Unsharp Mask controls

The Remove Grain effect contains Unsharp Mask controls, which increase the contrast of edges and fine details to help restore some of the sharpness that may have been lost during the grain reduction process.

Turbulent Noise effect

The Turbulent Noise effect uses Perlin noise to create grayscale noise that you can use for organic-looking backgrounds, displacement maps, and textures, or to simulate things like clouds, fire, lava, steam, flowing water, or vapor.

The Turbulent Noise effect is essentially a modern, higher-performance implementation of the Fractal Noise effect. The Turbulent Noise effect takes less time to render, and it’s easier to use for creating smooth animations. The Turbulent Noise effect also more accurately models turbulent systems, with smaller noise features moving more quickly than larger noise features. The primary reason to use the Fractal Noise effect instead of the Turbulent Noise effect is for the creation of looping animations, since the Turbulent Noise effect doesn’t have Cycle controls.

The Evolution controls create subtle changes in the shape of the noise. Animating these controls results in smooth changes of the noise over time, creating results that resemble, for example, passing clouds or flowing water.

This effect works with 8-bpc, 16-bpc, and 32-bpc color.

Controls

The fractal noise is created by generating a grid of random numbers for each noise layer. The Complexity setting specifies the number of noise layers. The Fractal Type setting determines the characteristics of this grid.

The type of interpolation to use between the random values in the noise grid.

Inverts the noise. Black areas become white, and white areas become black.

The default value is 100. Higher values create larger, more sharply defined areas of black and white in the noise, generally revealing less subtle detail. Lower values result in more areas of gray, softening or muting the noise.

Remaps color values that fall outside the range of 0–1.0, using one of the following options:

Remaps values so that any value above 1.0 is displayed as pure white, and any value below 0 is displayed as pure black. The Contrast value influences how much of the image falls outside this range. Higher values result in a mostly black and/or white image with less gray area. Therefore, higher contrast settings display less subtle detail. When used as a luma matte, the layer has sharper, better-defined areas of transparency.

Remaps values on an infinite curve so that all values stay in the range. This option reduces contrast and makes noise appear gray with few areas of pure black or pure white. When used as a luma matte, the layer contains subtle areas of transparency.

Remaps triangularly, so that values above 1.0 or below 0 fall back into the range. This option reveals subtle detail when Contrast is set above 100. When used as a luma matte, the layer reveals more detailed textured areas of transparency.

No remapping is performed. Values outside the range of 0-1.0 are preserved.

Settings to rotate, scale, and position the noise layers. The layers appear as if they are at different depths if you select Perspective Offset.

The number of noise layers that are combined (according to the Sub Settings) to create the noise. Increasing this number increases the apparent depth and amount of detail in the noise.

The noise is generated by combining layers of noise. The Sub Settings control how this combination occurs and how the properties of the noise layers are offset from one another. Scaling successive layers down creates finer details.

How much influence each successive layer has on the combined noise. At 100%, all iterations have the same amount of influence. At 50%, each iteration has half as much influence as the previous iteration. A value of 0% makes the effect appear exactly as if Complexity is 1.

The scale percentage of a noise layer relative to the previous noise layer.

Uses progressive revolutions that continue to change the image with each added revolution. This method is unlike typical revolutions that refer to a setting on the dial control for which the result is the same for every multiple of 360°. For Evolution, the appearance at 0° is different from the appearance at 1 revolution, which is different from the appearance at 2 revolutions, and so on.

You can specify how much the noise evolves over a period of time by animating Evolution. The more revolutions within a given amount of time, the more rapidly the noise changes. Large changes in the Evolution value over a short period of time may result in flashing.

Evolution Options

The amount by which the speed of smaller noise features differs from the speed of larger noise features. A value of 0 makes the movement of the noise resemble the noise generated by the Fractal Noise effect, in which smaller noise features move at the same speed as larger noise features. A larger value makes the multiple layers of noise appear to roil in a manner more like that of natural turbulence in a fluid.

Sets a random value from which to generate the noise. Animating the Random Seed property results in flashing from one set of noise to another (within that fractal type), which is usually not the result that you want. For smooth animation of noise, animate the Evolution property.

The opacity of the noise.

The blending operation between the noise and the original image. These blending modes are identical to the ones in the Modes column in the Timeline panel, with the following exceptions:

For a description of each blending mode, see Blending mode reference.

Renders the fractal noise only and does not composite on the original layer.

Renders the fractal noise as hue values instead of grayscale. The Saturation and Lightness of the original layer are maintained. If the original layer is grayscale, nothing happens.

Renders the fractal noise as saturation values instead of grayscale. The Hue and Lightness of the original layer are maintained. If the original layer is grayscale, nothing happens.