Adobe photoshop elements User Manual
CHAPTER 9
200
Applying Filters and Effects
Despeckle
Detects the edges in an image (areas
where significant color changes occur) and blurs
all of the selection except those edges. This blur-
ring removes noise while preserving detail.
all of the selection except those edges. This blur-
ring 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.
sharpening the image and hiding defects,
try various combinations of radius and threshold
settings. Or apply the filter on selected areas in
the image.
To use the Dust & Scratches filter:
1
Choose Filter > Noise > Dust & Scratches, or
use the Filters palette to apply the Dust & Scratches
filter.
filter.
2
If necessary, adjust the preview zoom ratio until
the area containing noise is visible.
3
Drag the Threshold slider left to 0 to turn off the
value, so that all pixels in the selection or image
can be examined.
can be examined.
The Threshold determines how different the
pixels’ values should be before they are eliminated.
pixels’ values should be before they are eliminated.
Note: The Threshold slider gives greater control for
values between 0 and 128—the most common range
for images—than for values between 128 and 255.
values between 0 and 128—the most common range
for images—than for values between 128 and 255.
4
Drag the Radius slider left or right, or enter a
value in the text box from 1 to 100 pixels. The
radius determines how far the filter searches for
differences among pixels.
radius determines how far the filter searches for
differences among pixels.
Adjusting the radius makes the image blurry. Stop
at the smallest value that eliminates the defects.
at the smallest value that eliminates the defects.
5
Increase the threshold gradually by entering a
value or by dragging the slider to the highest value
possible that eliminates defects.
possible that eliminates defects.
6
Click OK.
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 eliminating or reducing the effect of
motion on an image.
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 eliminating or reducing the effect of
motion on an image.
Pixelate filters
The filters in the Pixelate submenu sharply define
a selection by clumping pixels of similar color
values in cells.
a selection by clumping pixels of similar color
values in cells.
Color Halftone
Simulates the effect of using an
enlarged halftone screen on the image. The filter
divides the image into rectangles and replaces each
rectangle with a circle. The circle size is propor-
tional to the brightness of the rectangle.
divides the image into rectangles and replaces each
rectangle with a circle. The circle size is propor-
tional to the brightness of the rectangle.
To use the Color Halftone filter:
1
Choose Filter > Pixelate > Color Halftone,
or use the Filters palette to apply the Color
Halftone filter.
Halftone filter.
2
Enter a value in pixels for the maximum radius
of a halftone dot, from 4 to 127.
3
Enter a screen-angle value (the angle of the
dot from the true horizontal) for one or
more channels:
more channels: