Keying effects

Select the layer that you want to make partially transparent, and select Effect > Keying > Color Difference Key.

In the Effect Controls panel, select Matte Corrected from the View menu. 

To view and compare the source image, both partial mattes, and the final matte at the same time, select [A, B, Matte] Corrected, Final from the View menu. 

Learn about other views available in the View menu.

Select the appropriate key color:

• To key out a bluescreen, use the default blue color.
• To key out a non-blue screen, select a key color in one of the following ways:
  • Thumbnail eyedropper: Select and then use it in the Composition panel or the original thumbnail image on an appropriate area.
  • Key Color eyedropper: Select and then use it in the Composition or Layer panel on an appropriate area.
  • Key Color swatch: Select it and then a color from the specified color space.

Select the matte button to display the final combined matte in the matte thumbnail.

Select the Black eyedropper, and then click inside the matte thumbnail on the lightest area of black to specify transparent regions. The transparency values in the thumbnail and Composition panel are adjusted.

Select the White eyedropper, and then click inside the matte thumbnail on the darkest area of white to specify opaque regions. The opaque values in the thumbnail and the Composition panel are adjusted.

Select a matching accuracy from the Color Matching Accuracy menu. Select Faster unless you use a screen that isn’t a primary color (red, blue, or yellow). For those screens, select More Accurate, which increases rendering time but produces better results.

To further adjust transparency values, repeat steps 5 and 6 for one or both of the partial mattes. Select the Partial Matte B button or the Partial Matte A button to select a partial matte, and then repeat the steps.

Adjust transparency values for each partial matte and for the final matte by dragging one or more of the following sliders in the Matte Controls section:

• Black sliders adjust the transparency levels of each matte. You can adjust the same levels using the Black eyedropper.

• White sliders adjust the opaque levels of each matte. You can adjust the same levels using the White eyedropper.

• Gamma sliders control how closely the transparency values follow a linear progression. At a value of 1 (the default), the progression is linear. Other values produce nonlinear progressions for particular adjustments or visual effects.

When adjusting individual mattes, choose from the View menu to compare the mattes with and without adjustments:

• Select Uncorrected to view a matte without adjustments.

• Select Corrected to view a matte with all adjustments.

Before closing the Effect Controls panel, select Final Output from the View menu. Final Output must be selected for After Effects to render the transparency.

Select the layer that you want to make partially transparent, and select Effect > Obsolete > Color Key.

In the Effect Controls panel, specify a key color in one of two ways:

• Select the Key Color swatch to open the Key Color dialog box and specify a color.

• Select the eyedropper, and then a color on the screen.

Drag the Color Tolerance slider to specify the range of color to key out. Lower values key out a smaller range of colors near the key color and higher values key out a wider range of color.

Drag the Edge Thin slider to adjust the width of the border of the keyed area. Positive values enlarge the mask, increasing the transparent area and negative values shrink the mask, decreasing the transparent area.

Drag the Edge Feather slider to specify the softness of the edge. Higher values create a softer edge but take longer to render.

Select the layer that you want to make partially transparent, and select Effect > Keying > Color Range.

Select Lab, YUV, or RGB from the Color Space menu. If you have trouble isolating the subject using one color space, try using a different one.

Use the Key Color eyedropper and then select in the matte thumbnail to choose the area that corresponds to a color in the Composition panel you want to make transparent. Typically, this first color is the one that covers the largest area of the image.

Select the plus eyedropper, and then click other areas in the matte thumbnail to add other colors or shades to the range of colors keyed out for transparency.

Select the minus eyedropper, and then click areas in the matte thumbnail to subtract other colors or shades from the range of colors keyed out.

Drag the Fuzziness slider to soften the edges between transparent and opaque regions.

Use the sliders in the Min and Max controls to fine-tune the color range you selected with the plus and minus eyedroppers.

The L, Y, R sliders control the first component of the specified color space, the a, U, G sliders control the second component, and the b, V, B sliders control the third component.

Drag the Min sliders to fine-tune the beginning of the color range and drag the Max sliders to fine-tune the end of the color range.

Select a motion footage layer as the source layer.

In the source layer, find a frame that consists only of background, and save the background frame as an image file. Learn how to render and export a single frame of a composition.

Import the image file into After Effects, and add it to the composition.

The imported image becomes the difference layer. Make sure that its duration is at least as long as the duration of the source layer.

Turn off the display of the difference layer by selecting the Video   switch in the Timeline panel.

Make sure that the original source layer is selected, and then select Effect > Keying > Difference Matte.

In the Effect Controls panel, select Final Output or Matte Only from the View menu. 

Use the Matte Only view to check for holes in the transparency. Learn more about filling undesired holes after you complete the keying process.

Select the background file from the Difference Layer menu.

If the difference layer isn’t the same size as the source layer, select one of the following controls from the If Layer Sizes Differ menu:

Places the difference layer in the center of the source layer. If the difference layer is smaller than the source layer, the rest of the layer fills with black.

Stretches or shrinks the difference layer to the size of the source layer. Background images may become distorted.

Adjust the Matching Tolerance slider to specify the amount of transparency based on how closely colors must match between the layers. Lower values produce less transparency and higher values produce more transparency.

Adjust the Matching Softness slider to soften the edges between transparent and opaque areas. Higher values make matched pixels more transparent but don’t increase the number of matching pixels.

If the matte still contains extraneous pixels, adjust the Blur Before Difference slider. This slider suppresses noise by slightly blurring both layers before the comparison is made.

Before closing the Effect Controls panel, make sure to select Final Output from the View menu to ensure that After Effects renders the transparency.

Select the layer you want to make partially transparent, and select Effect > Keying > Extract.

If you are keying out bright or dark areas, select Luminance from the Channel menu. To create visual effects, select Red, Green, Blue, or Alpha.

Adjust the amount of transparency by dragging the transparency control bar in the following ways:

• Drag the upper right or upper left selection handles to adjust the length of the bar and to shorten or lengthen the transparency range. You can also adjust the length by moving the White Point and Black Point sliders. Values above the white point and below the black point are made transparent.

• Drag the lower right or lower left selection handles to taper the bar. Tapering the bar on the left affects the softness of transparency in the darker areas of the image; tapering it on the right affects the softness in the lighter areas. You can also adjust the softness levels by adjusting White Softness (lighter areas) and Black Softness (darker areas).

• Drag the entire bar left or right to position it under the histogram.

Select the border of the object that you want to extract by doing one of the following:

• Draw a single closed mask near the border of the object; then select the mask from the Foreground menu and leave the Background menu set to None. Adjust the Single Mask Highlight Radius to control the size of the border around this mask. (This method works well only on objects with simple edges.)

• Draw two closed masks– an inner mask just inside the object, and an outer mask just outside the object. Make sure that any fuzzy or uncertain areas of the object lie within these two masks. Select the inner mask from the Foreground menu and the outer mask from the Background menu.

If you want, move the masks around to find the location that provides the best results.

To extract more than one object, or to create a hole in an object, draw additional masks and then select them from the Additional Foreground and Additional Background menus. For example, to key out a person’s hair blowing in the wind against a blue sky, draw the inner mask inside the head, draw the outer mask around the outside edge of the hair, and then draw an additional mask around the gap in the hair where you can see sky. Select the additional mask from the Additional Foreground menu to extract the gap and remove the background image.

Create additional open or closed masks to clean up other areas of the image, and then select them from the Cleanup Foreground or Cleanup Background menu. Cleanup Foreground masks increase the opacity along the mask; Cleanup Background masks decrease the opacity along the mask. Use the Brush Radius and Brush Pressure options to control the size and density of each stroke.

Set Edge Thin to specify how much of the border of the matte is affected by the key. A positive value moves the edge away from the transparent region, increasing the transparent area; a negative value moves the edge toward the transparent region and increases the size of the foreground area.

Increase the Edge Feather values to soften edges of the keyed area. High Edge Feather values take longer to render.

Specify the Edge Threshold, which is a soft cutoff for removing low-opacity pixels that can cause unwanted noise in the image background.

Select Invert Extraction to reverse the foreground and background regions.

Set Blend With Original to specify the degree to which the resulting extracted image blends with the original image.

Select a layer as the source layer, and then select Effect > Keying > Linear Color Key.

In the Effect Controls panel, select Key Colors from the Key Operation menu.

Select a color space from the Match Colors menu. In most cases, use the default RGB setting. If you have trouble isolating the subject using one color space, try using a different color space.

In the Effect Controls panel, select Final Output from the View menu. The view you choose appears in the right thumbnail and in the Composition panel. To see other results, work in one of the other views:

Shows the original image without the key applied.

Shows the alpha channel matte. Use this view to check for holes in the transparency. 

Select a key color in one of the following ways:

• Select the Thumbnail eyedropper, and then select an appropriate area in the Composition panel or the original thumbnail image.
• Select the Key Color eyedropper, and then select an appropriate area in the Composition or Layer panel.
• To preview transparency for different colors, select the Key Color eyedropper, hold down the Alt key (Windows) or Option key (macOS), and move the pointer to different areas in the Composition panel or the original thumbnail image. The transparency of the image in the Composition panel changes as you move the pointer over different colors or shades. Click to select the color.
• Select the Key Color swatch to select a color from the specified color space. The selected color becomes transparent.

Adjust matching tolerance in one of the following ways:

• Select the Plus (+) or the Minus (-) eyedropper, and then click a color in the left thumbnail image. The Plus eyedropper adds the specified color to the key color range, increasing the matching tolerance and the level of transparency. The Minus eyedropper subtracts the specified color from the key color range, decreasing the matching tolerance and the level of transparency.
• Drag the matching tolerance slider. A value of 0 makes the entire image opaque; a value of 100 makes the entire image transparent.

Drag the Matching Softness slider to soften the matching tolerance by tapering the tolerance value. Typically, values under 20% produce the best results.

Before closing the Effect Controls panel, make sure to select Final Output from the View menu to ensure that After Effects renders the transparency.

In the Effect Controls panel or Timeline panel, turn off any current instances of keys or matte effects by deselecting the Effect option to the left of the key name or tool name. Deselecting the option causes the original image to appear in the Composition panel so that you can select a color to preserve.

Choose Effect > Keying > Linear Color Key. A second set of Linear Color Key controls appears in the Effect Controls panel below the first set.

In the Effect Controls panel, choose Keep Colors from the Key Operation menu.

Select the color you want to keep.

In the first application of the Linear Color Key effect, choose Final Output from the View menu in the Effect Controls panel, and then turn other instances of the Linear Color Key effect back on to examine the transparency. You may need to adjust colors or reapply the key a third time to get the results you need.

Select the layer that you want to make partially transparent, and select Effect > Obsolete > Luma Key.

Select a Key Type to specify the range to be keyed out.

Drag the Threshold slider in the Effect Controls panel to set the luminance value you want the matte to be based on.

Drag the Tolerance slider to specify the range of values to be keyed out. Lower values key out a smaller range of values near the threshold, while higher values key out a wider range of values.

Drag the Edge Thin slider to adjust the width of the border of the keyed area. Positive values make the mask grow, increasing the transparent area, while negative values shrink it.

Drag the Edge Feather slider to specify the softness of the edge. Higher values create a softer edge but take longer to render.

Select the layer from which you want to remove black or white backgrounds to isolate the subject, then go to Effect > Keying > Unmult.

The effect removes colors based on their brightness levels relative to the selected background color, so use the Background Color dropdown menu and select from the following options:

• If the background is black, you adjust the black level to remove darker areas while keeping the subject intact. ​
• If the background is white, you adjust the white level to remove brighter areas.

If you select the Background color as Black, use the Black Level slider in the Effect Controls panel to work with dark areas. 

Moving the slider handle to the left lowers the threshold, keeping more dark areas opaque. Moving it to the right raises the threshold, making more dark areas transparent.

If you select the Background color as White, use the White Level slider in the Effect Controls panel to work with the brighter areas. 

Moving the slider handle to the left lowers the threshold, removing colors that are brighter than the set value, while moving the slider to the right raises the threshold, keeping more of the brighter areas opaque.

Use the Softness slider to control the transition between transparent and opaque areas, creating a smoother gradient rather than a hard cutoff.

When the softness is set to 0, the transition is sharp, and as you increase the softness, it creates a gradual falloff. 

Select and enable the Remove Color Matting feature to restore the original, unblended colors of an image or footage by removing the influence of the background color from semi-transparent areas. ​

It works by identifying the background color (e.g., white) and proportionally removing it from semi-transparent areas. It then restores the colors to what they likely were before blending with the background. ​ For example, if red paint was blended against a white background, this feature tries to remove the white influence and restore the original red color. ​

Select and enable Clip HDR Results to limit color values in HDR footage to avoid extreme or unexpected results when working with negative values or values above 1 during the Remove Color Matting process.