Pages are clear and readable
(M) Pages are clear and readable
Complex diagrams or illustrations, such as maps or posters, may best be created as vector graphics with specialized software, such as Adobe Illustrator, and then converted to a raster format such as Portable Network Graphics (PNG) for the Web. Such images are easy to modify, can be resized without loss of quality, and can be printed as a high-resolution copy.
The choice of font, type size, line length and adjustments of the distance between groups of letters (tracking) and between pairs of letters (kerning) dramatically affect the legibility and readability of text whether on printed pages or on computer screens. Legibility incorporates both the perception of the text words, white space around the text, and how easily one can comprehend the content. Readability refers to how easily the text can be understood. Readability chiefly involves grammar, word choice, and sentence structure. Appropriate choices of fonts for the headings and body text, type size, line length (column width), the contrast between text colour and background colour, and white space surrounding the text all work to improve legibility.
Contrast. Avoid dull pages with little contrast as well as pages with too much contrast. On the other hand, there must be enough contrast between text and backgrounds to maximize the legibility of text. White or light-coloured text on a dark-coloured background is harder to read than dark type on a light background. This is especially true if the page gets printed (by either a colour or black & white printer).
(Website Guidelines pp. 62, 65, 68, 92, 139 (edited))