Wiley Photoshop CS4 Bible 978-0-470-34517-7 User Manual

amera film and photographic prints are not yet things of the past, 
and hopefully, there will always be a place for these beloved medi-
ums. But humans continue to be endowed with certain irresistible 

compulsions, not the least of which is the pursuit of convenience. The 
instant gratification of digital imaging, along with the improvement of its 
quality, has contributed to making it the standard of today.

On the downside, the convenience of this new technology comes with the 
inconvenience of having to learn new things. Thankfully, the eye-candy of 
imagery — and, of course, the anticipation of knowing how to nefariously 
alter friends’ photos — dulls the unpleasantness. Some might even say it 
makes it fun.

You can save digital images in many different file formats — for example, 
JPEG and TIFF — but there are formats and types within the file formats. 
The characteristics and types of digital images are discussed in this chapter 
so you can learn how to create the kind of images you need for specific 
purposes.

First, it is important to know that all digital images contain pixels, usually 
square in shape, that describe their colors and brightness levels. You can see 
an image’s individual pixels on-screen if you zoom in and look at a magni-
fied version, as shown in Figure 1.1.