Information and user interface components must be presentable to users in ways they can perceive. This principle covers text alternatives, time-based media, adaptable content, and distinguishable presentation.
Guideline 1.1: Text Alternatives
1.1.1 Non-text Content Level A
All non-text content presented to the user must have a text alternative that serves the equivalent purpose. This primarily means images need descriptive alt attributes. Crucible Scan checks for missing, empty, and suspicious alt text (e.g., filenames used as descriptions).
How to fix: Add meaningful alt text to every informational image. For decorative images, use an empty alt attribute (alt=""). For complex images like charts, provide a longer description nearby or via aria-describedby.
Guideline 1.2: Time-Based Media
1.2.1 Audio/Video-only (Prerecorded) Level A
Prerecorded audio-only and video-only content must have alternatives — a transcript for audio, a text description or audio track for video.
1.2.2 Captions (Prerecorded) Level A
All prerecorded audio in synchronized media must have captions.
1.2.3 Audio Description or Alternative Level A
An alternative for time-based media or audio description must be provided for prerecorded video.
1.2.4 Captions (Live) Level AA
Live audio content in synchronized media must have captions.
1.2.5 Audio Description (Prerecorded) Level AA
Audio description must be provided for all prerecorded video content.
Guideline 1.3: Adaptable
1.3.1 Info and Relationships Level A
Information, structure, and relationships conveyed through presentation must be programmatically determinable. Crucible Scan checks heading hierarchy, table structure, form label associations, and list markup.
How to fix: Use semantic HTML — proper heading levels, <label> elements for forms, <th> for table headers, and <ul>/<ol> for lists.
1.3.2 Meaningful Sequence Level A
Content reading sequence must be programmatically determinable when it affects meaning.
1.3.3 Sensory Characteristics Level A
Instructions must not rely solely on shape, color, size, visual location, orientation, or sound.
1.3.4 Orientation Level AA
Content must not restrict its view to a single display orientation unless essential.
1.3.5 Identify Input Purpose Level AA
The purpose of input fields collecting user information must be programmatically determinable.
Guideline 1.4: Distinguishable
1.4.1 Use of Color Level A
Color must not be the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.
1.4.2 Audio Control Level A
If audio plays automatically for more than 3 seconds, a mechanism must be available to pause, stop, or control volume.
1.4.3 Contrast (Minimum) Level AA
Text and images of text must have a contrast ratio of at least 4.5:1 (3:1 for large text). Crucible Scan automatically calculates contrast ratios for text elements.
How to fix: Adjust text color, background color, or both to meet the minimum ratio. Use a contrast checker tool to verify.
1.4.4 Resize Text Level AA
Text must be resizable up to 200% without assistive technology and without loss of content or functionality.
1.4.5 Images of Text Level AA
Text should be used to convey information rather than images of text, unless essential. Crucible Scan detects common image-of-text patterns.
1.4.10 Reflow Level AA
Content must be presentable without two-dimensional scrolling at 320 CSS pixels wide.
1.4.11 Non-text Contrast Level AA
UI components and graphical objects must have a contrast ratio of at least 3:1 against adjacent colors.
1.4.12 Text Spacing Level AA
No loss of content or functionality when text spacing is adjusted (line height, letter spacing, word spacing, paragraph spacing).
1.4.13 Content on Hover or Focus Level AA
Additional content triggered by hover or focus must be dismissible, hoverable, and persistent.