Converting Drawings to Accessible Images

Architectural drawings, engineering schematics, and other technical illustrations often contain handwritten annotations and complex visuals that make them difficult to interpret for individuals with disabilities. To comply with WCAG 2.1 AA, Section 508, and Title II of the ADA, drawings posted on bellevuewa.gov or related government websites must be accessible to all users, including those who rely on assistive technologies.

This guide outlines the key accessibility concerns associated with digital drawings and provides best practices for converting them into accessible formats.

Common Accessibility Issues in Drawings

1. Handwritten Annotations Are Difficult to Read

Issue: Handwritten notes may lack clarity, making them inaccessible to users with low vision or cognitive impairments.
Solution: Convert all handwritten annotations into typed text labels with a minimum contrast ratio of 4.5:1 for standard text and 3:1 for large text.

2. Screen Readers Cannot Interpret Image-Only Content

Issue: Static image files (e.g., scanned PDFs, JPEGs, PNGs) do not contain machine-readable text, preventing screen readers from conveying the information.
Solution: Provide a text-based summary of the drawing, outlining essential details in a structured format.

3. Missing Alternative Formats for Data Representation

Issue: Numeric values, such as slopes, dimensions, and measurements, are often embedded in the image and not provided elsewhere.
Solution: Include a data table summarizing key measurements and calculations in an accessible format.

4. Poor File Format and Structure

Issue: Posting drawings as unstructured PDFs or rasterized images limits accessibility.
Solution: Ensure that PDFs are tagged for screen readers, or use web supported image files (currently .png or .jpeg) with properly labeled elements when embedding this as media on a webpage.

How to Convert Drawings to an Accessible Format

Step 1: Convert Handwritten Annotations to Text

Use digital text for all labels and notes.
Ensure proper contrast between text and background.
Reference the city's Branding and Style Guidelines document, and use Open Sans (a sans-serif font) for better readability.

Step 2: Provide a Text-Based Description

Include a detailed summary of the drawing’s key components within the pdf and when labeling the image, or when referencing the image within the webpage's body copy.
Outline relevant details in compliance with applicable regulations (e.g. Washington building codes, etc.).

Step 3: Create an Alternative Data Table

If the drawing contains numeric values, provide a structured table summarizing:
- Measurements (e.g., angles, distances, area calculations).
- Compliance thresholds for regulatory standards.
- Structured tables include labeled headers.

Step 4: Choose an Accessible File Format

If using a PDF: Ensure that it is tagged and follows accessibility best practices. To tag PDFs, use Adobe Acrobat's Accessibility Tools, or alternative PDF tool's (e.g. Bluebeam) document features to tag PDF elements properly.
If embedding the drawing as an image on a webpage: Label elements with alt text and provide captions for better compatibility with assistive technologies.

Example: Before and After Accessibility Improvements

Accessibility Issue Original State Improved State Handwritten Annotations Notes are handwritten and hard to read. Text is digitally typed with proper contrast. Lack of Screen Reader Support Drawing is a static image with no text alternative. A full text-based description is provided. Missing Numeric Data in Text Form Measurements are embedded in the image. A separate data table is included. Inaccessible File Format Scanned PDF without proper tagging. Tagged PDF or image files with labeled elements, alt text, and captions.

Why This Matters

By implementing these changes, drawings posted as PDFs or Images on bellevuewa.gov are in compliance with ADA Title II WCAG 2.1 AA guidelines while improving accessibility for all users. These updates benefit:

Individuals with visual impairments using screen readers.
Users with cognitive disabilities who need clear, structured text.
General audiences who may struggle with poor contrast or handwriting.

Making drawings accessible enhances public engagement and ensures that all citizens can access critical planning information equitably.

For more guidance on accessibility compliance, refer to our other accessible resource articles in IT's knowledge base.