Blur and Sharpen effects

In general, blur effects sample the area around a pixel and assign to the pixel a new value that is the average of the sampled values. Increased blurriness is the result of increasing the size of the sample, whether the size is expressed as a radius or a length.

Some blur effects have a Repeat Edge Pixels option. Select this option to make the blur algorithm operate as if the pixel values beyond the edge of the layer are the same as the values of the edge pixels. This option keeps edges sharp, preventing them from darkening and becoming more transparent—the result of being averaged with a lot of zeroes. Deselect this option to make the blur algorithm operate as if the pixel values beyond the edge of the layer are zero.

Stu Maschwitz compares the Box Blur, Fast Blur, and Gaussian Blur effects in a post on his ProLost blog.

Third-party effects in this category included with After Effects:

• CC Cross Blur effect
  

• CC Radial Blur effect

• CC Radial Fast Blur effect

• CC Vector Blur effect

See Third-party plug-ins included with After Effects.

Applying an effect or preset

You can apply an effect or an effect preset by dragging it on to your composition from the Effects & Presets panel. To open the Effects & Presets panel, choose Window > Effects & Presets.

Bilateral Blur effect

The Bilateral Blur effect selectively blurs an image so that edges and other details are preserved. Areas with high contrast—where pixel values differ by a large amount—are blurred less than areas of low contrast.

The primary difference between the Bilateral Blur effect and the Smart Blur effect is that edges and details are still blurred a small amount by the Bilateral Blur effect. The result is a softer, dreamier look than that achieved by the Smart Blur effect with equivalent settings.

The result of the Bilateral Blur effect is very similar to the result of the Surface Blur filter in Adobe Photoshop.

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

The radius of the blur is automatically decreased in areas where an edge or other prominent detail feature exists. The Threshold value determines how the Bilateral Blur effect decides what areas contain features to be preserved and what areas to be blurred by the full amount. A lower Threshold value causes more fine details to be preserved. A higher Threshold value causes a more simplistic result, with fewer details preserved.

A larger radius for a blur means that more pixels are averaged together to determine each pixel value, so increasing the Radius value increases the blurriness.

When Colorize is not selected, the Bilateral Blur effect operates on one value for each pixel: its luminance value, which is a weighted average of its R, G, and B color channel values. The result is a monochromatic image.

When Colorize is selected, the Bilateral Blur effect operates on each color channel individually. The result is a color image.

Box Blur effect

Box Blur is similar to Fast Blur and Gaussian Blur, but Box Blur has the added advantage of an Iterations property, which allows you to control the quality of the blur.

Stu Maschwitz compares the Box Blur, Fast Blur, and Gaussian Blur effects in a post on his ProLost blog.

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

How many times the blur is sequentially applied to the image. A value around 3 gives a blur similar in quality to Fast Blur. A higher number of iterations creates smoother transitions between colors and increases the blur, but it also increases the render time. The default value creates boxy results.

Camera Lens Blur effect

The effect is a replacement for the Lens Blur effect. The effect has a larger blur radius (500), and is much faster than the Lens Blur effect. The Camera Lens Blur effect also does not disable Render Multiple Frames Simultaneously multiprocessing, as its predecessor did.

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

Iris properties include Shape, Roundness, Aspect Ratio, Rotation, and Diffraction Fringe.

Creates a halo around the edge of an iris that simulates light bending, concentrating around the edge of the iris blades. When set to 100, a natural normal halo that is based on the area represented in the shape of the blur is visible. At 500, all the energy of the blur is pushed from inside the blur to the ring/halo. This effect, in essence, emulates a catadioptric lens.

A control layer can be used as a blur map to affect Camera Lens Blur effect properties.

Layer to use as the blur map.

Luminance, color, or alpha channel for the blur map.

The value from the control layer that corresponds to zero blurring. The difference between the Blur Focal Distance value and a value from the control layer dictates the amount of blurriness for the corresponding area on the layer with the effect applied.

Modifies color values of the pixels that are above the threshold. Higher highlight values produce the best results for getting a good blooming blur/glow effect.

The amount of energy fed into pixels that are above the threshold. Depending on how bright a pixel is above the threshold, the pixel value is increased in brightness by this relative amount.

The luminosity limit on what is boosted by Gain. Pixels much brighter than the threshold are boosted more than those pixels slightly above it. Setting the threshold to 0 boosts any pixel with a brightness higher than 0. Setting it to 1 effectively eliminates any highlight (unless the image contains overbrights).

The amount of color retained in the boosted pixel. Setting it to 0 pushes the boosted colors toward white (what the old Lens Blur effect used to do). Setting to 100 attempts to retain as much color as possible. This saturation of the highlights is especially noticeable in situations with colored lights (like a city scape at night), in which the colors create a multicolored tapestry of bokeh.

See About Blur & Sharpen effects for information about how Repeat Edge Pixels options are treated in blur effects.

Produces a result similar to a project set to a linearized working color space. Check this property (or set it from the project settings) to see realistic bokeh effects from your images.

Forward and backward compatibility

If the Camera Lens Blur effect is added to an After Effects CS5.5 and later project, and then saved as an After Effects CS5 project (see Save and back up projects in After Effects CS5.5 and later.), a warning appears stating that the effect is missing. Projects created in After Effects CS5 or earlier using the Lens Blur effect retain that effect when opened in After Effects CS5.5 and later. However, you cannot directly apply the Lens Blur effect in After Effects CS5.5 or later.

Camera-Shake Deblur effect

Camera-Shake Deblur effect helps you recover blurry footage caused by camera shake. You can stabilize a shaky footage with Warp Stabilizer VFX effect, but unwanted artifacts like motion blur may still exist. Camera-Shake Deblur effect reduces the unwanted artifacts to produce better results. The effect targets blurry frames and tries to reconstruct them by using sharp on either side of the blurry frame. Camera-Shake Deblur effect uses optical flow technology to blend the sharp frames with the blurry frames.

Applying Camera-Shake Deblur effect

To apply the effect, do any of the following:

• To view it from the Effect menu, select Effects > Blur & Sharpen > Camera-Shake Deblur.

Camera-Shake Deblur effect provides you with a set of properties to control the effect performance.

To open the properties, follow these steps:

Camera-Shake Deblur effect properties

• Blur Duration: Changes the number of frames to compare around the blurry frame to get a non-motion-blurred frame. The Blur Duration property controls the number of frames for which motion blur lasts. Select a lower value for shorter period of shake, and a higher value for longer period of shake. 
• Deblur Method: Uses the optical flow method, which affects how pixels are mapped from the non-motion-blurred frames to the blurry frame. You can choose between High Quality (slower) and Standard quality. High Quality (slower) provides more accurate results, but takes longer to process. Standard is fast and provides standard production-quality results.
• Strength: Controls how much correction is applied to the blurry frame. You can adjust the strength values from 100% (default) to 200% depending on how blurry a frame is. Higher values can result in artifacts if the non-motion-blurred frames within the blur duration are not aligned properly with the blurry frames.
• Shake Sensitivity: Determines the threshold of whether a frame is considered blurry enough to need deblurring. Lower Shake Sensitivity value deblurs only the blurriest frames and may not be able to identify other motion blurs. Higher Shake Sensitivity value is sensitive to any kind of motion blur and tries to deblur any motion blur identified. 

Tip: For best results, apply Camera-Shake Deblur effect after stabilizing footage. For example, apply the Warp Stabilizer VFX effect first, then apply Camera-Shake Deblur effect.

Camera-Shake Deblur effect in After Effects

Channel Blur effect

The Channel Blur effect individually blurs the red, green, blue, or alpha channels of a layer.

Compound Blur effect

The Compound Blur effect blurs pixels in the effect layer based on the luminance values of a control layer, also known as a blur layer or blurring map. By default, bright values in the blur layer correspond to more blurring of the effect layer, while dark values correspond to less blurring; select Invert Blur for light values to correspond to less blurring.

This effect is useful for simulating smudges and fingerprints, or changes in visibility caused by atmospheric conditions such as smoke or heat, especially with animated blur layers such as those generated with the Turbulent Noise effect.

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

The maximum amount, in pixels, that any part of the affected layer can be blurred.

Stretches the control layer to the dimensions of the layer to which it is applied; otherwise, the control layer is centered on the effect layer.

Directional Blur effect

The Directional Blur effect gives a layer the illusion of motion.

Andrew Kramer provides a video tutorial on his Video Copilot website in which he demonstrates the use of the Directional Blur effect to make a gun slide look as if it is moving quickly.

This effect works with 8-bpc, 16-bpc, and 32-bpc color. The effect uses GPU acceleration for faster rendering.

The direction of the blur. The blur is applied equally on either side of the center of a pixel; therefore, a setting of 180° and a setting of 0° produce the same results.

Fast Box Blur effect

The effect can replicate the rendering result of Fast Blur (Legacy), but at a faster speed. To apply the effect, select Effect > Blur & Sharpen > Fast Box Blur. The Fast Box Blur effect is rendered using the GPU of your computer.

Gaussian Blur effect

The Gaussian Blur effect blurs and softens the image and eliminates noise. The quality setting of the layer doesn’t affect Gaussian Blur. 

This effect works uses the Repeat Edge Pixels option and works with 8-bpc, 16-bpc, and 32-bpc color. The effect uses GPU acceleration for faster rendering.

The Gaussian Blur effect is a replacement for the Gaussian Blur (Legacy) effect and produces slightly different rendering result than the Gaussian Blur (Legacy) effect.

Radial Blur effect

The Radial Blur effect creates blurs around a point, simulating the result of a zooming or rotating camera.

You can specify the level of anti-aliasing applied at Best quality; no anti-aliasing is applied at Draft quality. At Draft quality, the blur appears grainy. You may prefer the draft results for special effects, but the grain may flicker on interlaced displays.

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

Spin blurs in arcs around the Center point, as if the camera were rotating; Amount specifies degrees of rotation. Zoom blurs radially outward from the center point; Amount specifies the length of the blur.

Sharpen effect

The Sharpen effect increases the contrast where color changes occur. The quality setting of the layer doesn’t affect Sharpen.

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

The Sharpen effect uses GPU acceleration for faster rendering.

Smart Blur effect

The Smart Blur effect blurs an image while preserving lines and edges within the image. For example, you can use the Smart Blur effect to smoothly blur shaded areas while retaining crisp outlines of text and vector graphics.

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

How far the filter searches for dissimilar pixels to blur.

How different the values of pixels should be before they are eliminated.

What parts of the image receive the blur. Normal specifies that the blur be applied to the entire selection, whereas Edge Only and Overlay Edge specify that the blur be applied only to the edges of color transitions. Where significant contrast occurs, Edge Only applies black-and-white edges, and Overlay Edge applies white.

Unsharp Mask effect

The Unsharp Mask effect increases the contrast between colors that define an edge.

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

The distance from the edge at which pixels are adjusted for contrast. If you specify a low value, only pixels near the edge are adjusted.

The greatest difference between adjacent pixels for which contrast isn’t adjusted. A lower value produces a greater result. A value that is too low causes contrast for the entire image to be adjusted and can generate noise or cause unexpected results.