Adobe AFTER EFFECTS 7.0 - Removing Grain in Frame Sequences; To Add Temporal Filtering to a Sequence; To Sharpen an Image with Unsharp Mask Controls

ADOBE AFTER EFFECTS 7.0
User Guide
360
Preview Displays the current settings of the applied effect in a 200 x 200 pixels area.
Blending Matte Shows the current color matte or mask, or the combination of both, which results from the current
settings of the Blend With Original controls group.
10 Choose Final Output from the Viewing Mode control.
Removing grain in frame sequences
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 particularly effective in removing compression artifacts from DV
or video footage. Because temporal filtering works on the basis of differences between frames, it is useful only for
sequences.
To properly evaluate the results of this filter, the sequence must be viewed in real time, either with a RAM preview
or by viewing a movie rendered to a file.
To add temporal filtering to a sequence
1
Apply the Remove Grain effect to your image.
2 PlacetheRemoveGrainpreviewregionovertheareaoftheimagethathasthemostsubtlechangesfromframeto
frame or that has the most moving image detail.
3 Select Enable in the Temporal Filtering controls.
4 Adjust the Amount value to 100%.
5 Create a RAM preview of the sequence or render it.
6 If you see unwanted streaking or blurs around moving objects, reduce the Motion Sensitivity value, and then
preview or render it again.
7 Try the following techniques if you want to improve the results:
• To quickly reduce the noise of a sequence that has a lot of buzzing noise, set the Noise Reduction value to zero and
the Temporal Filtering Amount to 100%, and render the sequence.
• To speed up previews, apply temporal filtering to your sequence after all the settings for a single frame have been
adjusted.
• To retain a layer’s effects and also apply temporal filtering to it, precompose the selected layer (choose Layer >
Precompose), and then apply the Remove Grain effect to that layer.
To 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.
❖ Do any of the following:
• Increase the Unsharp Mask controls Amount value to obtain acceptable sharpening without generating
undesirable artifacts or bringing back too much grain.
• Increase the Threshold value to remove any unwanted artifacts that resulted from the sharpening.
• Adjust the Radius to change the area over which Unsharp Mask finds details.
• AdjusttheNoiseReductionvalueuntiltheimagejustbeginstolosesharpness;thendecreasethevaluealittle,and
then apply the Unsharp Mask controls to sharpen the image.