Test Case sc1.4.3_l2_017: Contrast for foreground text and background image

Formal Metadata

Formal Metadata
TitleContrast for foreground text and background image
DescriptionDocument containing text on a background image specified via CSS.
CreatorBenToWeb (johannes.koch@…)
RightsCopyright BenToWeb 2004-2007
LanguageEnglish
Date2005-08-11
Statusdraft

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 fail because the luminosity contrast ratio is lower than 5.

Expert Guidance

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

Test Modes

Accessibility expert.

Test Files

Test file.

TCDL Data

sc1.4.3_l2_017 (XML).

Rules

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

Primary Rules

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

Functional Outcome

The foreground and background colours don't have enough contrast.

Technical Comment

The luminosity contrast ratio is 4.35.

This test case does not map to a WCAG 2.0 technique or failure.

Secondary Rules

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

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

Functional Outcome

The foreground and background colours don't have enough contrast.

Technical Comment

Online version: sc1.4.1_l2_017.

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

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