5.3b Web site design usability principles
Use of flash
The FAO Web Quality Assurance Checklist recommends that the use of Flash or other interactive animation plugins should not be used for navigation or design effects. They should only be used for specialised elements such as interactive maps or tutorials.
In addition, the link for downloading these plugins should point to the official download page and not to a locally copied executable file. Many FAO Web users live in developing countries with slow connections and lengthy download times. Therefore, please make sure that the use of interactive animation is necessary and ensure that the file size is as small as possible.
Colours can affect the usability of your Web site. Reading on a computer monitor can be difficult, so make sure your colour choices do not force the reader to squint! Most commercial Web sites use a white background with black text. Dark text on a light background offers the highest contrast and is the easiest to read. Finding text colours that contrast strongly with the background is important. If you deviate from this, make sure you have a good reason.
The VisiBone Web site allows you to experiment with colour combinations.
Fonts and font size
Experts advise using an 11 or 12 point font size on Web sites to increase readability. At FAO, the font size you see on most Web sites is 11 point. The Web Content Accessibility Guidelines 2.0 of the W3C suggest using relative rather than absolute units for font size. Using the relative length unit "em" allows all browsers to resize the text.
Readability strongly depends on font face; for example verdana or arial fonts are much more readable on the screen than the "times" font. FAO Web sites commonly use sans-serif fonts, e.g. verdana, Geneva, arial and Helvetica.
Try to keep font size and font style consistent throughout the site!
Keep colours and fonts consistent
Visitors should never click on an internal link of your site and wonder if they have left the site. Consistent use of colours and fonts throughout the site helps readers know they are still with you.
Accessibility, usability and search engine optimization
Special attention needs to be given to accessibility in the development of Web sites to ensure they are usable by people with different types of disabilities using a wide range of devices and assistive technologies.
Improving accessibility also increases search engine optimisation.
It is much more productive to consider this aspect at the start of a project rather than modify an inaccessible site once published.
Interface and technical quality
Providing a consistent visual identity improves the usability of the FAO Web site as well as reinforcing a more coherent online presence. This strengthens the role of the FAO domain as a gateway to the Organization’s knowledge.
Applying the technical quality criteria set out in the FAO Web Quality Assurance Checklist will ensure that the FAO’s target audiences can access and effectively interact with the Organization. It will also help ensure that the site is easy to navigate and have a commonality of appearance throughout.