Adobe InDesign CS3 - Manual (Page 335)

INDESIGN CS3
User Guide
328
You can freely move or modify vector graphics without losing detail or clarity, because they are resolution-
independent—they maintain crisp edges when resized, printed to a PostScript printer, saved in a PDF file, or
imported into a vector-based graphics application. As a result, vector graphics are the best choice for artwork, such
as logos, that will be used at various sizes and in various output media.
The vector objects you create using the drawing and shape tools in Adobe Creative Suite are examples of vector
graphics. You can use the Copy and Paste commands to duplicate vector graphics between Creative Suite compo-
nents.
See also
“About bitmap images” on page 328
About bitmap images
Bitmap images—technically called raster images—use a rectangular grid of picture elements (pixels) to represent
images. Each pixel is assigned a specific location and color value. When working with bitmap images, you edit pixels
rather than objects or shapes. Bitmap images are the most common electronic medium for continuous-tone images,
such as photographs or digital paintings, because they can more efficiently represent subtle gradations of shades and
color.
Bitmap images are resolution-dependent—that is, they contain a fixed number of pixels. As a result, they can lose
detail and appear jagged if they are scaled to high magnifications on-screen or if they are printed at a lower resolution
than they were created for.
Example of a bitmap image at different levels of magnification
Bitmap images sometimes require large amounts of storage space, and often need to be compressed to keep file sizes
down when used in certain Creative Suite components. For instance, you compress an image file in its original appli-
cation before you import it into a layout.
Note: In Adobe Illustrator, you can create bitmap effects in your artwork using filters, effects, and graphic styles.
See also
“About vector graphics” on page 327
Image resolution guidelines for final output
Bitmap images contain a fixed number of pixels, usually measured in pixels per inch (ppi). An image with a high
resolution contains more, and therefore smaller, pixels than an image of the same printed dimensions with a low
resolution. For example, a 1-inch-by-1-inch image with a resolution of 72 ppi contains a total of 5184 pixels (72
pixels wide x 72 pixels high = 5184). The same 1-inch-by-1-inch image with a resolution of 300 ppi would contain a
total of 90,000 pixels.
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3:1