Adobe 65011817 User Guide - Page 76

Add noise to an image, Add noise

Page 76 highlights

USING FIREWORKS CS4 70 Working with bitmaps An increase in radius results in a greater area of sharp contrast surrounding each pixel edge. 5 Drag the Threshold slider to select a threshold of 0 to 255. Values between 2 and 25 are most commonly used. An increase in threshold sharpens only those pixels of a higher contrast in the image. A decrease in threshold includes pixels of lower contrast. A threshold of 0 sharpens all pixels in the image. Add noise to an image When viewed at high magnification levels, most images obtained from digital cameras and scanners do not have perfectly uniform colors. Instead, the colors you see consist of pixels of many different colors. In image editing, noise refers to these random color variations in the pixels that make up an image. Sometimes, such as when you are pasting part of one image into another, the difference in the amount of random color variation in the two images can stand out. This can prevent the images from blending together smoothly. In such a case, add noise to one or both images to create the illusion that both images come from the same source. You can also add noise to an image for artistic reasons-for instance, to simulate an old photograph or static on a television screen. Original photograph; after adding noise Add noise 1 Select the image. 2 Do one of the following to open the Add Noise dialog box: • In the Property inspector, click the plus (+) icon next to the Filters label, and select Noise > Add Noise from the Filters pop-up menu. • Select Filters > Noise > Add Noise. Note: Applying a filter from the Filters menu is destructive; that is, it cannot be undone except when Edit > Undo is an option. To maintain the ability to adjust, turn off or remove this filter, and then apply it as a Live Filter as described in the first bulleted option in this step. For more information, see "Using Live Filters" on page 117. 3 Drag the Amount slider to set the amount of noise. Values range from 1 to 400. An increase in amount results in an image with more randomly placed pixels. 4 Select the Color option to apply color noise. Deselect the option to apply monochrome noise only. 5 Click OK. Last updated 3/8/2011

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70
USING FIREWORKS CS4
Working with bitmaps
La
s
t updated 3/8/2011
An increase in radius results in a greater area of sharp contrast surrounding each pixel edge.
5
Drag the Threshold slider to select a threshold of 0 to 255.
Values between 2 and 25 are most commonly used. An increase in threshold sharpens only those pixels of a higher
contrast in the image. A decrease in threshold includes pixels of lower contrast. A threshold of 0 sharpens all pixels
in the image.
Add noise to an image
When viewed at high magnification levels, most images obtained from digital cameras and scanners do not have
perfectly uniform colors. Instead, the colors you see consist of pixels of many different colors. In image editing,
noise
refers to these random color variations in the pixels that make up an image.
Sometimes, such as when you are pasting part of one image into another, the difference in the amount of random color
variation in the two images can stand out. This can prevent the images from blending together smoothly. In such a
case, add noise to one or both images to create the illusion that both images come from the same source. You can also
add noise to an image for artistic reasons—for instance, to simulate an old photograph or static on a television screen.
Original photograph; after adding noise
Add noise
1
Select the image.
2
Do one of the following to open the Add Noise dialog box:
In the Property inspector, click the plus (+) icon next to the Filters label, and select Noise
> Add Noise from the
Filters pop-up menu.
Select Filters
> Noise
> Add Noise.
Note:
Applying a filter from the Filters menu is destructive; that is, it cannot be undone except when Edit
> Undo
is an option. To maintain the ability to adjust, turn off or remove this filter, and then apply it as a Live Filter as
described in the first bulleted option in this step. For more information, see “
Using Live Filters
” on page
117.
3
Drag the Amount slider to set the amount of noise.
Values range from 1 to 400. An increase in amount results in an image with more randomly placed pixels.
4
Select the Color option to apply color noise. Deselect the option to apply monochrome noise only.
5
Click OK.