Test Case sc1.4.3_l2_003: Sufficient contrast between foreground text and background text

Formal Metadata

Formal Metadata
TitleSufficient contrast between foreground text and background text
DescriptionDocument containing text on a background text.
CreatorBenToWeb (johannes.koch@…)
RightsCopyright BenToWeb 2004-2007
LanguageEnglish
Date2005-08-11
Statusvalidated

Technologies and Features

Technologies are markup languages or data formats. If the technology is a markup language, “features” refers to elements and attributes.

XHTML™ 1.0 The Extensible HyperText Markup Language (Second Edition)

XHTML™ 1.0 The Extensible HyperText Markup Language (Second Edition)

CSS 2.0 Specification

CSS 2.0 Specification

Test Data

Purpose

The test is intended to pass because the luminosity contrast ratio between foreground text colour/background colour and foreground text colour/background text colour is higher than 5.

Expert Guidance

The formula to be used for calculating the luminosity contrast ratio can be found in http://www.w3.org/TR/2006/WD-WCAG20-20060427/appendixA.html#luminosity-contrastdef.

Test Modes

Three or more accessibility experts.

Test Files

Test file.

TCDL Data

sc1.4.3_l2_003 (XML).

Rules

“Rules” refer to success criteria in WCAG 2.0, checkpoints in WCAG 1.0 and similar requirements.

Primary Rules

The test case passes (line 5, column 28) the following success criterion: http://www.w3.org/TR/2007/WD-WCAG20-20070517/Overview.html#visual-audio-contrast-contrast.

Functional Outcome

The foreground and background colours have enough contrast.

Technical Comment

The luminosity contrast ratio between foreground and background text colour is 7.50, between foreground text and background colour 15.60.

This test case maps to technique G18: Ensuring that a contrast ratio of at least 5:1 exists between text and background behind the text

Secondary Rules

Secondary Rule (WCAG 2.0 - April 2006 Working Draft (Last Call))

The test case passes (line 5, column 28) the following success criterion: http://www.w3.org/TR/2006/WD-WCAG20-20060427/guidelines.html#visual-audio-contrast-contrast.

Functional Outcome

The foreground and background colours have enough contrast.

Technical Comment

Online version: sc1.4.1_l2_003.

Secondary Rule (WCAG 2.0 - June 2005 Working Draft)

The test case needs review before it can be established if it passes or fails the following success criterion: http://www.w3.org/TR/2006/WD-WCAG20-20050630/#visual-audio-contrast-contrast.

Functional Outcome

It is not clear if there is sufficient colour contrast for some people with low vision.

Technical Comment

The WCAGWG hasn't provided threshold values for colour contrast yet.