Accessibility & Readability in Signage: Contrast, Sizing & Legibility

Why Readability Matters in Signage

The purpose of signage is communication. Whether it’s a shopfront, wall graphic, vehicle wrap, or building sign, your message must be instantly understood.

Good readability:

• improves visibility from a distance

• helps customers find and recognise your business

• ensures compliance in many public spaces

• improves brand professionalism

• reduces miscommunication

• works in a wide range of lighting conditions

High-impact readability is essential for strong Exterior Signage, especially in busy environments.

Contrast: The Most Important Factor

Contrast determines how easily people can read a sign at a glance.

High Contrast Examples

• White text on black

• Black on white

• Dark blue on white

• Yellow on black

• White on deep red or navy

These combinations work in bright sun, shade, glare, and twilight.

Low Contrast Examples

• Red on black

• Grey on white

• Blue on black

• Pastels on pastels

• Low-contrast gradients

Low contrast reduces legibility at all distances.

Indoor design often plays more creatively with colour, but readability must still come first — especially for Interior Branding elements like reception signs, directional labels, and office text.

Font Selection for Signage

The Best Fonts for Readability

• Sans-serif fonts

• Even stroke widths

• Clear geometric shapes

• Good letter spacing (kerning)

• Balanced line height

These fonts remain consistent at distance and don’t lose definition when viewed at angles.

Fonts to Avoid

• Decorative scripts

• Condensed or compressed typefaces

• Ultra-thin strokes

• High-contrast serif fonts

• Overly stylised branding fonts for main messaging

Stylised fonts can still be used — but ideally for supporting design elements, not the primary message.

More file preparation advice is in our Artwork & File Preparation guide.

Minimum Text Sizes by Viewing Distance

Letter height is just as important as DPI. Here’s a simplified reference for real-world readability.

Pedestrian Range (0–5 metres)

• Reception signs

• Interior panels

• Directional wayfinding

Recommended letter height: 20–70 mm

Short-Range Exterior (5–15 metres)

• Shopfronts

• Window graphics

• Retail street frontage

Recommended letter height: 100–150 mm

See relevant examples in Window Graphics.

Vehicle-Readable (10–30 metres)

For vehicles, readability is influenced by:

• viewing distance

• speed

• angle

• movement

Recommended letter height for primary branding (business name): 150–250 mm

Supporting text on vehicles can be much smaller (e.g., services, phone numbers, URL), but:

• it should still be readable at typical following distances

• it must contrast strongly

• the main brand name should always follow the larger recommended sizing

More vehicle-specific guidelines appear under Vehicle Graphics.

Long-Range / Building Signage (30–100 metres)

• High-mounted building signs

• Large ACM panels

• Road-visible signage

Recommended letter height: 250–450 mm+

See more under Building Signage.

Backgrounds, Patterns & Visual Noise

Even if your text is large enough, the background affects how readable it is.

Reduce Background Interference

• Avoid busy textures behind text

• Use solid colours for important messaging

• Minimise strong gradients

• Avoid overlaying text on photos unless heavily faded or blurred

Glare & Gloss

Gloss surfaces reflect light, which can hide thin details or lighter colours. This is especially noticeable on shopfront windows.

Patterns are particularly tricky on Window Graphics, where reflections already reduce contrast.

Lighting & Viewing Conditions

Lighting changes throughout the day, and the readability of your sign changes with it.

Key considerations:

• Direct sunlight reduces contrast and increases glare

• Shadowed areas reduce brightness

• Street lighting affects night visibility

• Backlit letters look sharper if the font is bold enough

• Front-lit signs can wash out thin strokes

Illuminated signage requires special care with contrast and thickness.

Accessibility Considerations

Accessible signage isn’t just for compliance — it makes your sign readable to everyone.

Best Practices

• Use universally readable colour combinations

• Avoid relying solely on red/green differences (colour blindness)

• Provide generous spacing between letters

• Avoid overly condensed fonts

• Keep stroke widths consistent and above minimum thickness

• Avoid very faint pastel colours

• Ensure text is visible from wheelchair height in indoor spaces

High accessibility increases clarity for all readers, not just those with impairments.

Designing Readable Signage Files

Even the best design can lose quality if prepared incorrectly for print.

Checklist:

• Always use vector text where possible

• Ensure stroke thickness is sufficient before scaling

• Don’t rasterise text unnecessarily

• Avoid stretching fonts disproportionately

• Maintain correct contrast when exporting colour profiles

• Check readability at 100% scale before exporting

• Ensure any logos supplied as raster files meet their size requirements

These steps work alongside DPI principles from our Viewing Distance & DPI guide.

Summary: Clarity Beats Complexity

Readable signage combines:

• strong contrast

• clear, simple fonts

• correct letter sizing for distance

• minimal visual clutter

• thoughtful colour choices

• awareness of lighting conditions

• proper file preparation

Good signage is noticed. Great signage is understood instantly.

See more guides in the resource hub