13 Working with Bitmaps
A bitmap represents an image as a mosaic of colored dots called pixels. The
pixels are arranged in a fixed number of rows and columns. Bitmaps are
also known as raster images, and the method used to create them is called
rasterization.
When a bitmap is edited, the color values of its pixels are changed to form
the new image.
The following color modes are supported:
Black and
White
Each pixel is either black or white, with no shades of gray.
Grayscale
Pixels are colored in 256 shades of gray ranging from solid
black to solid white.
RGB
The color values for each pixel are expressed as a combination
of red, green and blue values. Up to 16.7 million different
colors can be reproduced under this color model.
CMYK
The color values for each pixel are expressed as a combination
of cyan, magenta, yellow and black values. This is the color
mode most commonly used in color printing.
Indexed
The color of each pixel is indicated by a reference to a separate
swatch table containing 256 colors.
If a bitmap is magnified or printed at too low a resolution, the individual
pixels become visible. This gives the image a jagged, pixilated appearance
(see above).
Resolution is the number of pixels displayed per unit of printed length in an
image, usually measured in pixels per inch (PPI) or dots per inch (DPI).
Using DesignCentral
When a bitmap is selected, DesignCentral shows the Bitmap and Profile
tabs.
© 2006 SA International
Bitmap Tab
The Bitmap tab will show some attributes of selected bitmaps. On this tab
you can change the resolution of the bitmap. Changing the resolution will
automatically change the bitmap’s size. Uncheck the Proportional option
to set different resolutions for horizontal and vertical direction.
Profile Tab
On this screen you can specify the Input profile and the Rendering
intent that will be used as settings to print a particular bitmap. You can
have independent settings for each bitmap. See “Configuring the System for
Color Printing” on page 130 for more information.
Image Size
File Size
Original
Resolution
Color Mode
Color Depth
File Location
Resolution
Setting
Bitmap tab
Profile tab
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