Text size, style, blinking elements and Readability

This is a technique for testing:

WCAG 2.0: Guideline 2.3 Seizures: Do not design content in a way that is known to cause seizures. Understanding Guideline 2.3

2.3.1 Three Flashes or Below Threshold: Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds. (Level A) Conformance Requirement 5: Non-Interference. How to Meet 2.3.1 | Understanding 2.3.1

Guideline 3.1 Readable: Make text content readable and understandable. Understanding Guideline 3.1

Overview

Readability focuses both on the way the web page has been designed as well as the content. "Photosensitive seizures can be provoked by certain types of flashing in Web or computer content, including mouseovers that cause large areas of the screen to flash. Hazardous, seizure-inducing content has been inadvertently broadcast on television in the past, causing mass seizures in children. As Web content becomes more dynamic and media-rich, it is important to prevent similar problems." (Trace 2007).

We are also highlighting issues of text size and style as the content in Web 2.0 sites varies widely depending on the market for which the service is aimed.   

Authors need to be aware that acronyms, complex vocabulary and obscure terms may not be recognised by some users and those commenting or adding to wikis etc. must be careful to maintain similar standards.

The text size, style and other features relating to the appearance of web pages are often dependent on the way the site has been developed.  Those adding content to sites using online rich text editors are rarely offered many options for being creative with text size and style unless there is the ability to use Hypertext Markup Language. The output is not always guaranteed to turn out as expected! Some users prefer sans serif fonts such as Arial or Helvitica to serif fonts such as Times New Roman.    

Method

It is easy to see whether an item is flashing or blinking and causing distraction (example of flashing text from NCAM) The test can be completed manually. Try to work through a whole site as there may be many pages with different types of flashing content – it is often the advertisements that blink. If you have concerns download the Trace Photosensitive Epilepsy Analysis Tool (PEAT)

The checks need to include the fact that the text is real text and not a graphic that cannot be read by a screen reader.  The fonts need to be a good size (“Clear print fonts have a minimum type size of 12 point” Tiresias).  The style should be simple with good contrast levels as mentioned in the contrast checks.  

It is hard to find specific advice as to which are easiest to read fonts (Webaim offer examples of sans serif fonts) or the right size but there must be the opportunity for users to make changes (background and text colour as well as size).

The ability to make these changes can be tested using the Accessibar toolbar in Firefox.  It is also possible to use browser ‘options’ to change these features as described in the BBC My Web My Way.

font changes

Checking for Readability is difficult as has been mentioned but there are online tests with scores for the number of complex multisyllabic words used in sentences as well as sentence length based on the Fog and Flesch Scales as provided by Juicy Studio.   There is also the NIACE Readability Project that may help with the checks.

Advice