User's Manual

520

ADOBE PHOTOSHOP CS2

User Guide

Noise filters

The Noise filters add or remove noise,orpixelswithrandomlydistributed colorlevels. This helpstoblend aselection

into the surrounding pixels. Noise filters can create unusual textures or remove problem areas, such as dust and

scratches.

Add Noise Applies random pixels to an image, simulating the effect of shooting pictures on high-speed film. You

canalsouse theAdd Noisefiltertoreducebandinginfeathered selections or graduatedfills or to give amorerealistic

look to heavily retouched areas. Options for noise distribution include Uniform and Gaussian. Uniform distributes

color values of noise using random numbers between 0 and plus or minus the specified value, creating a subtle effect.

Gaussian distributes color values of noise along a bell-shaped curve, creating a speckled effect. The Monochromatic

option applies the filter to only the tonal elements in the image without changing the colors.

Despeckle Detectsthe edgesinanimage (areas wheresignificant colorchangesoccur) andblurs allofthe selection

except those edges. This blurring removes noise while preserving detail.

Dust & Scratches Reduces noise by changing dissimilar pixels. To achieve a balance between sharpening the image

and hiding defects, try various combinations of Radius and Threshold settings. Or apply the filter on selected areas

in the image. See also “To use the Dust And Scratches filter” on page 520.

Median Reduces noise in an image by blending the brightness of pixels within a selection. The filter searches the

radius of a pixel selection for pixels of similar brightness, discarding pixels that differ too much from adjacent pixels,

and replaces the center pixel with the median brightness value of the searched pixels. This filter is useful for elimi-

nating or reducing the effect of motion on an image.

Reduce Noise (Photoshop only) Reduces noise while preserving edges based on user settings affecting the overall

image or individual channels.