Font colors in the fontcolor plugin for the Atto HTML editor lack sufficient color contrast with the default background color.

WCAG 2.0 level AA requires a contrast ratio of 4.5:1 for normal text and 3:1 for large text (18 point or larger). Level AAA requires a contrast ratio of 7:1 for normal text and 4.5:1 for large text. See WCAG 2.0 Guideline 1.4.1.

Current contrast ratios:
Red contrast ratio: 3.75:1 (fails level AA and AA for normal text; fails AAA for large text)
Yellow contrast ratio: 1.48:1 (fails level AA and AA for normal text; fails AA and AAA for large text)
Green contrast ratio: 1.48:1 (fails level AA and AA for normal text; fails AA and AAA for large text)
Blue contrast ratio: 1.48:1 (fails level AA and AA for normal text; fails AA and AAA for large text)

These colors are in conformance with the Web Content Accessibility requirements at the AAA Level:

• Red: #a20000
• Green: #006000
• Blue: #004d83
• Purple: #800080
• Magenta: #980068
• Gray: #3c3c3c

Tests were conducted with the Paciello Group’s Colour Contrast Analyser and with WebAIM’s Color Contrast Checker.