Computer-related injuries - Colour & contrast
Extract: Every visual presentation involves figure-ground relationships. This relationship between a subject (or figure) and its surrounding field (ground) will evidence a level of contrast; the more an object contrasts with its surrounds, the more visible it becomes ...


RE: Color Contrast (forum)

Extract: I put that in to help with the headaches some people get from the eye-strain of looking at a white background.  I don't see why it can't be a recommendation and not a success criteria ...


Computer-related injuries
Extract: Suggestions to reduce the risk of eyestrain include:
- Make sure your primary light source (such as a window) isn't shining into your face or directly onto the monitor.
- Tilt the monitor slightly to eliminate reflections or glare.
- Make sure your computer screen isn't too close to your face.
- Position the screen so that it is either at eye level, or slightly lower.
- Reduce the contrast and brightness of your screen by adjusting the controls on the monitor.
- Frequently look away from the screen and focus on faraway objects
- Have regular eye examinations to check that blurring, headaches and other associated problems aren't caused by any underlying disorders.


Color and Pattern
Extract: So, when you choose colors, remember that:
· Your eyes cannot focus clearly on blue, which is why it is such a good background color and such a bad foreground color.
· Nor can your eyes focus well on red, but red has the advantage (if you need it) of "moving forward" in the visual field.
· Yellow and green are just as visible in the periphery as they are as in the center of the visual field.
· Black and white are equally visible throughout the visual field (Horton 1991, 228).
· For most colors, hue seems to change as luminance increases or decreases.
· However, saturated blue, green, and yellow remain constant throughout the range of luminance. Use them when constancy is important.
· Staring at a large patch of a saturated color for a long time shifts color perception towards its complement. For example, when you look up after working on a bright red figure, everything will look greenish. Called the "McCullough effect."
· In bright light, red seems brighter than blue. In dim light, however, blue appears lighter but colorless, while red appears nearly black. In low-light situations, avoid reds. Called the "Purkinje effect."


A Dozen Things You Should Know about Eyestrain
Extract: The most overlooked cause of eyestrain in offices is contrast - usually, a dark screen surrounded by a bright background such as a window or a lit wall. The best solution is to find a way to darken the area around the screen. This problem occurs mainly on screens with light letters on a black background.


Colour allocation strategies
Extract: Graphical workstations and high-end personal computers are generally equipped with 24 bit truecolour displays - pixels can independently be set to any desired colour. 8 bits (256 levels) of red, green, and blue are available giving 16.7 million displayable colours. (Highly technical article)


Selecting Colors
Extract: Limit your color choices to 2 or 3 and use them in a consistent manner across the entire site. Using too many colors makes a page appear cluttered and distracts the eye.
· Regardless of the colors you choose, remember to select colors for text and background that have sufficient contrast to make them readable both on- and off-line.
· Avoid 'Vibration' There are certain color combinations that should be avoided because they 'vibrate' visually when put together.


Combining colors
Extract: ... in general one can say that the risk of using too many colours is greater than the risk of using too few. Too many colours will make the page feel too busy and it usually makes it harder for the viewer to find the information he or she wants. It is also more tiring to the eyes.

A page with too few colours, on the other hand, risks being seen as a bit boring, but this need not always be the case. One commonly used rule in these matters is to use three colours. Primary colour: ... the main colour of the page. It will occupy most of the area and set the tone for the design as a whole. Secondary colour: ... usually there to "back up" the primary colour. It is usually a colour that is pretty close to the primary colour. Highlight colour: ... used to emphasize certain parts of the page ... contrasts more with the primary and secondary colours ... should be used with moderation.

Readability and Backgrounds
Extract: Some web sites have dark blue or dark purple text on a black background. I've even seen blue backgrounds with blue text on top that's only a shade different. The only way you can read the text on sites like these is to highlight it. Most people who understand even a little about color know they should not use red text on a blue background, or blue text on a red background because the human eye cannot focus on red and blue at the same time. The text seems to vibrate which causes eye strain.


Eye Comfort Exercises
Extract: 1. Blinking (produces tears to help moisten and lubricate the eyes)
2. Yawning (produces tears to help moisten and lubricate the eyes)
3. Expose eyes to natural light


Eye Resources on the Internet
» An enormous list of links


Color & Vision database
Extract: These Web pages provide an annotated library of easily-downloadable standard data sets relevant to color and vision research. The focus of this site is primarily scientific and technical, but some introductory background information is also provided.


Work Safe Work Better
Extract: Your work surface should be uncluttered, easy to clean, neither too dark nor too light in colour and the layout should be conducive to the work you do.

» Online tools to assist with colour matching

Color schemer online

ZSPC Super Color Chart