Accessibilty for content providers - design
The designers of your website would want you to avoid having to be involved with any of the issues here, since it will mean that you are breaking away from the options in the stylesheets. In general, the more you use mark up to reflect the meaning and structure of your content the better. That makes it easier to maintain over a long period of time, to provide a common user experience across the site and to adapt to changes in the overall look and feel.
The reality is that there are times when you can’t avoid it - have deadlines to meet and you know that the stylesheet won’t be amended in time. So these are the WCAG 1 checkpoints that you need to be aware of.
Colour
A Priority 1 requirement is:
2.1 Ensure that all information conveyed with color is also available without color, for example from context or markup.
You’ll have come across the application of this checkpoint when you’re filling in forms. There was a time when you would have had a phrase like ‘Required fields are marked in red’. That’s not particularly helpful for a screen reader that doesn’t report on colours to the user, so now the convention is to use a ‘*’ either as a replacement or in addition. So if you are using colour to highlight say the main contacts in a list then you will need to follow a similar convention.
Font sizes
A Priority 2 requirement (i.e. for Double-A compliance) is:
3.4 Use relative rather than absolute units in markup language attribute values and style sheet property values.
You’ll come across this mainly when changing the size of text. The first thing to check is that you do want to use this option & that you shouldn’t be using a heading style instead. If that’s not the case then you need to avoid using points (pt) or pixels (px) as the measurement unit and instead use ems (em), percentages (%) or the relative sizes (xx-small, x-small, small, medium, large, x-large, xx-large).
There’s no real difference in the choice between ems and percentages as 1em equivalent to 100% (.5em is 50%, 1.5em is 150%, etc.).
This is mainly intended to help people who are using the text resizing option in Internet Explorer which ignores any absolute units. Other browsers (and now IE7) have a zoom option that will enlarge/reduce all the text on the page no matter what units have been used.
Blinking
7.2 Until user agents allow users to control blinking, avoid causing content to blink (i.e., change presentation at a regular rate, such as turning on and off).
This might have been more of a concern when the guidelines were originally framed (1999) than it is today - the <blink> tag. So if you haven’t come across any other reason to avoid it like the plague then here’s one. It’s required for Priority 2 compliance.
Summary
- It’s better to have the stylesheets changed overall than to format directly in the content
- Don’t use colour alone to provide meaning
- Use ems, percentages or the relative units (i.e. small, medium, etc.) to change the size of text rather than pixels or points
- Don’t use the blink tag (restrain yourself, it’s horrible)
