When designing your website, don’t forget you are designing for the computer screen, which has drawbacks. Problems you need to think about that don’t occur in the print world. Your design must be portable, usable with low bandwidth, present easy information access and provide clear presentation.

Portability - visitors use different browsers, different operating systems and different computer hardware. There are still older browsers around. Internet Explorer, Firefox, Mozilla and Netscape can render web pages differently. Netscape version 4 will mangle your beautifully designed CSS layout. A variety of operating systems are currently in use, and the most popular are PC based windows, Macintosh, Linux and Unix.

So, you need to perform compatibility testing otherwise you cannot be sure your pages will work. Build a user profile so you can test what you think your ideal visitor will use. Which browser to test depends on what’s currently in use. Wikipedia shows the browser market share and there are statistics available to estimate the importance of each test option.

Bandwidth - your website must be accessible at different connection speeds. It might be quick as a flash on your broadband but how does it work on dial-up? Web surfers are impatient and will hit the back button if your site loads too slowly. Keep your image sizes low and test your pages at low speeds.

Easy access - you need to have an ‘information design’. Your site content must be meaningful, easily navigable and have a minimum of distractions. What’s the purpose of a visit to your site? What’s the user’s path as he navigates around your site? Think of different visitor needs and design for them.

Presentation - computer screens are poor resolution, compared to print, so on-screen reading tires your eyes and you can get glare. Make it easier for your visitor. Choose one or two fonts and colours. Design with visual harmony in mind. Group relevant content and separate with white space. Use contrast. Employ headings. Summarise your content and link it to more detail.

Although sitepoint is a busy site, the designers have created visual harmony with blue and orange colours, consistent fontstyles, using plenty of white space and summarising content with a link to more detail.

So, if you want to employ good usability standards on your website, test portability, bandwidth, access and presentation against your ideal visitor. If you don’t you might never know your design is broken.

During the next post I will discuss usability and visual themes.