In 2002 it was reported that air traffic controllers in Hampshire, UK were complaining that the text on their computer screens was too small and that they were having difficulty telling the difference between 0, 6, and 8. A Health and Safety Executive report claimed the text was at the "limits of readability".
Colour and font schemes
Many ordinary people find it difficult to read from a computer screen with the standard colours and fonts. Most operating systems allow users some control over the colours and size of screen elements. This can make access much easier, as long as software applications respect these colour and font choices.
In Microsoft Windows, you can try out different colour and font schemes using the Ease of Access Center in Windows Vista, the Accessibility Wizard in earlier Windows versions, or the Control Panel Display options in Windows 95.
Good inclusively designed software will pick up user colour and font preferences from the operating system. If this is not possible, then software should offer some choice of colours within the application itself. At the very least, there should be one or more pre-set alternative colour schemes based on what is likely to benefit most users.
People with sight problems often require high contrast colour schemes and/or reverse colours (ie light text on a dark background), and sans serif fonts without justification for blocks of text (ie left-aligned). People with dyslexia often prefer less high contrast, with pastel background colours.
Don't convey information using colour or other visual characteristics
People who are colour blind as well as those with vision impairments will have difficulty if an important aspect of software depends upon being able to distinguish colour. An example would be if the printer status is indicated by the same icon coloured either red or green. There should be some text-based indication in addition to the colour coding.
Screen reader users may have a similar difficulty if capitals, bold or italic font is used. We suggest that this is supplemented by additional text or readable symbols. As an example, if field labels are bold to indicate mandatory entries in a form, a symbol such as an asterisk could be added at the start of the field label.
Menu items that are dimmed or 'greyed out' do not need additional text, because this status is conveyed to screen readers via the programmatic interface.
Field labels
The positioning and programming of labels is surprisingly controversial. Software designers have strong views on the style and appearance of their handiwork! We sometimes find it difficult to convince them that accessibility and usability are sometimes more important than an attractive visual layout that presents barriers to its users. It should be possible to produce a modern, stylish, yet accessible and usable interface.
For someone using magnification, it is important for the field label to be as close as possible to the contents, otherwise it will not be visible at the same time as the input cursor and the user has to do extra work to find out what a field contains. By convention, the label for edit fields should be located to the left of the field, while radio buttons and checkboxes are labelled to the right. Consistency of positioning is very important.
It is also important for the label to be programmatically associated with the control it relates to. While we are able to associate labels with controls by assessing a screen layout visually, this is not possible for a screen reader user. This is covered further in the section about the programmatic interface.