Scrollbars, buttons, etc.- Smaller than a Component. Highly reusable items, used many times, over and over, in other places. Some similar sized items are not widgets, because they are custom implemented items. This definition (#1 only)except mobile scale is smaller, so don't include Pop-Ups, and we put a few things like scrollbars somewhere else for organization.

Conspicuity with Color

Conspicuity, while involving legibility, also implies other display characteristics. It describes how well an object can be detected while it captures a user’s attention amongst other noise or other competing information.

Color coding

Color can be used to classify, label, and emphasize information displayed on a screen. When using color for these things, you need to understand that we have limits in our processing abilities that affect our signal detection.

Opponent Processing Theory

In 18xx, A German psychologist Ewald Hering theorized that there are six elementary colors that are arranged perceptually as opponent pairs along three axes. These pairs are: black-white, red-green, and yellow-blue. Each color either is positive (excitatory) or negative (inhibitor). These opponent colors are never perceived at the same time because the visual system cannot be simultaneously excited and inhibited.

Our modern color theory stems off of this. Today, we know that the input from the cones is processed intro three distinct channels: The luminance channel (black-white) is based on input from all of the cones. We have two chromatic channels. The red-green channel is based on the difference of long and middle-wavelength cone signals. The yellow-blue channel is based on the difference between the short-wavelength cons and the sum of the other two (Ware, 2000).

In 1986, Post and Green created an experiment to test how subjects could effectively name 210 colors on a computer screen. The results of that test that are worth noting are:

Color for Labeling

or more technically – nominal information coding, is used to because color can be an effective way to make objects easy to remember and visually classify.

Perceptual factors to be considered in choosing a set of color labels:

  1. Distinctness:

  2. Unique hues: Based on the Opponent Theory, they are: Red, Green, Yellow, Blue, Black, and White.

  3. Contrast with background: Our eyes are edge detectors. When we have objects that must be in front of a variety of backgrounds, it may be beneficial to have a thin white or black border around the color-coded object. Consider the reasons why alert street signs, have the border, too.

  4. Color blindness: About 7% of males and only 0.5% of females are color blind in some way. The most common is being red-green color blind.

  5. Number: We are limited in the number of color-codes we can rapidly perceive. Studies recommend use between five and ten codes.

  6. Field Size: Object size affects how you should color code. Small color-coded objects less than half a degree of visual angle and in the yellow-blue direction range should not be used to avoid the small-field colorblindness.

  7. Conventions: When using color-naming conventions, be cautious of cultural differences.

Color Semantics

Common conventions are: red =hot, danger, blue=cold, green=life, environmental, go. In China, red =life, good fortune, green =death.

Color Conspicuity Guidelines For Mobile Devices