Lighthouse International - Making Text Legible

http://www.lighthouse.org/accessibility/legible/

Home > Accessibility > Making Text Legible

Making Text Legible

Designing for People with Partial
Sight
by Aries Arditi, Ph.D
Here are basic guidelines for making effective legibility
choices that work for nearly everyone.
How does impaired vision affect reading?
Impaired vision often makes reading difficult by:
Reducing the amount of light that enters the eye
Blurring the retinal image
Damaging the central portion of the retina best suited toreading
Light reduction and blurring reduce the effective contrast of thetext, while central retinal damage impairs the ability to see small
print and to make eye movements that are crucial to reading.

1. Contrast
Text should be printed with the highest possible contrast. There isgood evidence that for many readers who are older or partiallysighted, light (white or light yellow) letters on a dark (black)background are more readable than dark letters on a light
2 of 7

1/25/2009 2:50 AM

Lighthouse International - Making Text Legible

simulation of acataract.

http://www.lighthouse.org/accessibility/legible/

background. However, the traditional dark on light may beaesthetically preferable.

View more vision
simulations here.

2. Type Color
Very high contrasts are difficult to achieve with color combinations
other than black and white. Printed material, generally, is mostreadable in black and white. Different colors may be important foraesthetic or other reasons, but it is better to use suchcombinations only for larger or highlighted text, such as headlines
and titles.

3. Point Size
3 of 7

1/25/2009 2:50 AM

Lighthouse International - Making Text Legible

http://www.lighthouse.org/accessibility/legible/

Type should be large, preferably at least 16 to 18 points, but keep
in mind that the relationship between readability and point size
differs somewhat among typefaces.

4. Leading
Leading, or spacing between lines of text, should be at least 25 to
30 percent of the point size. This is because many people withpartial sight have difficulty finding the beginning of the next line
while reading.

5. Font Family
Avoid complicated, decorative or cursive fonts and, when they

4 of 7

1/25/2009 2:50 AM

Lighthouse International - Making Text Legible

http://www.lighthouse.org/accessibility/legible/

must be used, reserve them for emphasis only. Standard serif orsans-serif fonts, with familiar, easily recognizable characters arebest. Also, there is some evidence that sans-serif fonts are morelegible when character size is small relative to the reader's visualacuity.

6. Font Style
While there is little reliable information on the comparative
legibility of typefaces, there is some evidence that a roman
typeface, using upper and lower cases, is more readable thanitalics, oblique or condensed.

7. Letter Spacing
Text with close letter spacing often presents difficulties for readers
who are partially sighted, especially those with central visual field

5 of 7

1/25/2009 2:50 AMLighthouse International - Making Text Legible

http://www.lighthouse.org/accessibility/legible/

defects. Where possible, spacing should be wide. Monospaced fonts
rather than proportionally spaced fonts seem to be more legible forthese readers.

8. Margins
Extra-wide binding margins are especially helpful in bound material
because it makes it easier to hold the volume flat. Spiral binding
can be helpful as well. Many visual devices, such as stand- andvideo-magnifiers, are easiest to use on a flat surface.

9. Paper Finish
Paper with a glossy finish can lessen legibility because manypeople who are older or who have partial sight also have problems

6 of 7

1/25/2009 2:50 AM

Lighthouse International - Making Text Legible

http://www.lighthouse.org/accessibility/legible/

with glare.

10. Distinctiveness
Visual impairment often makes it difficult to find a book or otherdocument that is buried among similar publications, especially forsets with volumes that differ only in title or number. Use of
distinctive colors, sizes and formats on the covers can be especiallyhelpful to older individuals and those who are partially sighted.
Designers can help to compensate for the difficulty experienced byreaders who are partially sighted by following the guidelines in thisbrochure.

What You Can Do
Sign Up for Our e-newsletter!
Become a Volunteer
Find Help Near You

Copyright © 2009 Lighthouse International. All rights reserved.
Site Map |Employment Opportunities | Contact Us | Donate Now! |Privacy Policy | Sign Up for Newsletters

7 of 7

1/25/2009 2:50 AM