Contents
What is WCAG contrast?
WCAG 2 “Contrast Ratio” In WCAG 2, contrast is a measure of the difference in perceived “luminance” or brightness between two colors (the phrase “color contrast” is never used). This brightness difference is expressed as a ratio ranging from 1:1 (e.g. white on white) to 21:1 (e.g., black on a white).
What does the Web Content Accessibility Guidelines WCAG say is the minimum contrast ratio between text on a foreground and color on a background to earn a AA rating?
G18: Ensuring that a contrast ratio of at least 4.5:1 exists between text (and images of text) and background behind the text.
What is non text contrast?
Success Criterion 1.4. 11 Non-text Contrast (Level AA): The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s): Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.
What is good color contrast?
Alternating colors, such as blue and yellow, produce the best combinations since they have good contrast in both hue and value. Black contrasts well with any color of light value and white is a good contrast with colors of dark value. For example, yellow and black are dissimilar in the contrast of both hue and value.
Is a 1000 1 contrast ratio good?
The projector is still casting a bit of light in those areas, because its contrast ratio is not high enough. Remember, a high contrast ratio (i.e., 100,000:1) means darker blacks, and a low contrast ratio (i.e., 1000:1) means brighter, more visible “gray” blacks.
How do you check non text contrast?
The best way to check this is to use a colour contrast checker. There are many contrast checkers available but our preferred tool is the WebAIM colour contrast checker, because you can specifically check for this requirement.
What is non text content?
1 Non-text Content (Level A): All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed below. Controls, Input. If non-text content is a control or accepts user input, then it has a name that describes its purpose.