Datasheet

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Part I ✦ Welcome to Photoshop
Figure 1-1: When printed small, an image appears smooth and
sharp (left). But when enlarged, the now-visible individual pixels
create a grainy image (right).
The downs and ups of drawing
The process of creating a vector-based drawing might more aptly be termed
“constructing,” because you actually build each of the lines and shapes, point
by point, and stack them on top of each other to create a finished image. Each
of these objects is independently editable — one of the main advantages of an
object-oriented approach — but you’re still faced with the task of building your
artwork one chunk at a time.
Because a drawing program defines lines, shapes, and text as mathematical equa-
tions, these objects automatically conform to the full resolution of the output device,
whether it’s a laser printer, an imagesetter, or a film recorder. The drawing program
sends the math to the printer and the printer renders the math to paper or film. In
other words, the printer converts the drawing program’s equations to printer pixels.
Your printer offers far more pixels than your screen — a 600-dots-per-inch (dpi) laser
printer, for example, offers 600 pixels per inch (dots equal pixels), whereas most
screens are limited to 150 pixels per inch or fewer. So the printed drawing appears
smooth and sharply focused regardless of the size at which you print it, as shown
in Figure 1-2.
Figure 1-2: Whether printed small or viewed through a high-level zoom,
this image remains crisp and clear.
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