A Complete Guide to Web Design

38 Chapter 3 – Web Design Principles for Print Designers

Graphics on the Web

Web Design in a Nutshell, eMatter Edition

1. Choose ImageÝ AdjustÝ Gamma.


2. Select Macintosh-to-Windows to adjust for Windows display, or select
   Windows-to-Macintosh to adjust for Mac display.


3. Click OK.
   You can also apply a manual gamma adjustment by moving the Gamma slider or
   entering a value in the text box between 0.1 and 9.99.
   Images created with Photoshop 4.0 need to have their gamma adjusted for display
   in Windows because Photoshop 4.0 uses the Mac OS gamma value as its default.
   Photoshop 5.0, however, uses the Windows gamma value as its default (even
   when displayed in Mac OS), so graphics created in version 5.0 require no adjust-
   ment for proper display in Windows.

Be Aware of File Size

It goes without saying that graphics have made the Web what it is today; however,

as a web designer, you should know that many users have a love/hate relation-

ship with graphics on the Web. Remember that graphics increase the time it takes

a web page to move across the network; large graphics mean substantial down-

load times, which can try the patience of the reader, particularly one dialing in on

a standard modem connection.

Here is the single most important guideline a web designer can follow:Keep the

file size of your graphics as small as possible!The nature of publishing over a

network creates a new responsibility for designers to be sensitive to the issue of

download times.

Detailed strategies for minimizing graphic file size for each file format appear in

Chapters 14 through 16 in Part III of this book.

Getting correct file sizes on a Macintosh

It is important for web designers to pay attention to file size, measured in bytes or

kilobytes (K). On Windows computers, the indication of file size that appears in

the directory listing is an accurate measure of the file’s actual size. The number the

Macintosh Finder shows, however, is almost always inaccurate. This is because of

how the Finder displays file sizes and how Macs encode files.

Partition sizes.For one thing, the file size listings in the Finder are measured in

even partition units or “blocks,” and the larger your hard drive the larger the

block. For instance, on a four-gigabyte hard drive, the smallest block size is 65K,

so even if a file contains only 1K of information, it will display as 65K in the

Finder.

You can use the Finder’s Get Info command to get an accurate reading of how

many bytes are actually in the file. To open the Get Info box, highlight the file

name in the Finder, then select FileÝGet Info, or use the Command-I keyboard

shortcut. The actual number of bytes appears in parentheses next to Size.

This is not the case for all Macintoshes, however. Macs with the newer HFS Plus

hard-disk formatting allow variable block sizes, which allow the Finder to indicate