Our understanding of color is shaped by both how our eyes work and how our brains process information. Because of this, variables like saturation, hue, brightness, and contrast can guide a user's attention and behavior. Trends in color palettes or shades can also contribute to a positive UX. To improve engagement, color choice is an essential step.
Hue is often thought to be the same thing as color, but it actually is a component of color. Color is comprised of three aspects: hue, value, and saturation (p. 4). Hue (also called pigment) is "yellow" or "purple", what we usually think of as a color (p. 4). Value is how light or dark something is. Mackiewicz describes a color with a low value looking "more blackish" while one with a high value looking "more whitish" (p. 4). Saturation is how bright or dull something is.
Color should absolutely be implemented in small amounts in order to improve usability. In harnessing color theory, technical writers can direct attention to certain elements, create associations and sections, prioritize relevant information (making it stand out), and organize in an easy-to-understand manner (p. 6).
The ability to read a document, especially on a webpage, is the most important factor when creating a piece of technical writing. There is no way to interact with content if it cannot be read. "Research shows that, regardless of color combination, contrast equates to greater readability in print" (p. 7). This is why black text on white background is best for printed documents, as it has the highest level of contrast. However, it is still important to consider saturation and hue pairs when deciding on color.
Although a color scheme may seem effective in theory, it is important to note that there are several situations in which certain colors or hues can appear to shift, which could in turn result in the opposite effect of the one intended. One of these scenarios is light text on a dark background. This will instantly make the text color look much brighter than if it were on a lighter hue- think of how blinding white text is when put against a black background versus a mid-toned gray. The surface area of the color is also important. Bright yellow will read well when the font is in a large size and bold, but that formula is not ideal for smaller-sized font because color can look less saturated over a smaller surface area. I chose this color as an example because Murch himself mentions that yellows specifically in addition to blues tend to be "susceptible to small-area color loss" (p. 18). Red and green can also sometimes "mix" and be processed by the eye as yellow when "in smaller areas" (p. 18).
It is a given that every person experiences color differently, and therefore every person has different preferences and associations with every color. Pastel colors may be cute to one user and nauseating to another. Interestingly enough, it is found that a person can adapt to saturation levels, making the colors eventually appear softer after extended exposure. At the same time, using a color super saturated may cause eye strain or fatigue. Although it is impossible to account for all users on the color selection of one interface, the color scheme should at least be chosen to hit the perfect point of saturation.
Taking the above into account, Murch organized a set of guidelines to use when selecting colors for use in technical documents. He separated it into three categories: physiological, perceptual, and cognitive (p. 18).
Physiological:
Don't use "extreme color pairs" like red and blue or yellow and purple, especially in highly saturated tones (p. 19).
Don't use "pure blue" for anything sharp, thin, or small (p. 19).
Use a higher brightness for anything catered towards older audiences (p. 19).
To improve focus and make colors distinguishable, make sure there is a visible level of contrast (p. 19).
Red and green are poor colors for peripheral displays, try yellow and blue instead (p. 19).
Avoid single-color distinctions when catering to colorblind audiences (p. 19). For an example of a color palette that works for colorblindness, see the Introduction.
Perceptual:
Be careful choosing background and text colors in tandem, not all colors work against others (p. 19).
Use achromatic (black, white, grey) colors for fine detail like text and chromatic colors for grabbing attention to prevent the human eye from mistakenly merging hues (p. 20).
Cognitive:
Don't go overuse color. Again, stick to color as an attention grabbing device (p. 20).
Use the same background color for corresponding elements (p. 20).
Use similar colors to represent similar connotations (p. 20).
Saturation levels can be matched with the level of importance in order for the user's attention to be drawn to the most important (and therefore most saturated) part (p. 20).
Arrange multiple colors in an effective order. ROYGBIV, also known as rainbow order, is one example of a natural or effective order (p. 20).
Color schemes on webpages and even the logos displayed on those pages can illicit an emotional response from the viewer. These responses are usually a result of personal connotations with certain colors, and those connotations can be formed by "individual experience and cultural convention" (p. 41). Green, for example, is usually associated with the Earth or agriculture, and that may be why Green Giant chose the color for its website and logo. It connects them with "the material world" (p. 41). However, color choices are constantly changing due to "social, political, and cultural reasons" (p. 44). Above all else, trendy color palettes may be the most effective to consider for webpages.