Icon Categories and Conventions73
Design Tips
A common format for web icons is transparent PNGs, but if
you chose to use this le format, remember to check your
target audience and the compatibility with older browsers. If a
transparent PNG isn’t compatible with a browser it will show the
transparent area as a solid background. Internet Explorer 6 can
show transparent PNGs with some extra coding but it isn’t an
ideal solution and can cause some compatibility issues across
browsers. Some developers don’t nd PNG to be a problem as
they have a very small percentage of users running incompatible
browsers, and others will nd it extremely important to design for
all audiences. If you want maximum compatibility across browsers
then the .GIF format is a good option as it has universal support
for its transparency, however it also has the drawback of only
rendering bit-transparency, which won’t allow you to use gradual
percentages of opacity.
With navigation icons, sometimes simple is best. Using a glyph
style is a good way to assist users without distracting them from
the main focus of the page. Be sure to make glyphs as clear and
precise as possible. Pixel blurring is even more obvious on a
symbol than it is on a regular icon. For more on precise rendering
techniques go to page 78.
With icons used as illustrative content for a webpage, carefully
chose the style that you want to use. Icons can often infer a
meaning that you may not be aware of. A common mistake is
websites using highly polished icons that use Mac or PC style
imagery. What can often happen when using icons in this way is
that you may lead viewers to believe that you’re selling software
or have software to accompany a product or service. This has
largely come about because of two factors. One is the popularity
of web design for the application and software markets, in the
uptake of this style some designers have also used the same style
icons without realizing why they were used in the original designs.