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Number of posts in this thread: 4 (In chronological order)

From: David Ashleydale
Date: Mon, May 14 2012 4:02PM
Subject: 1.4.3 Contrast (Minimum) - Large-scale text
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Hi,

WCAG 1.4.3 Contrast (Minimum) refers to "large-scale" text and defines it
as being at least 18 point or 14 point bold.

For one thing, I find this odd because the recommendation for 1.4.4 Resize
Text is to not use "fixed" font sizes like points. Is 1.4.4 still valid in
today's web environment?

For another, what's the best way to determine what "18 point" is in other
measurement systems? There is a note attached to the definition for
large-scale that says 18 point is "roughly" equivalent to 1.5 em or 150%.
And it says, "When fonts are defined in relative units, the actual point
size is calculated by the user agent for display. The point size should be
obtained from the user agent, or calculated based on font metrics as the
user agent does, when evaluating this success criterion." How does one go
about doing this? Am I safe in telling my developers that "large-scale"
text in this case (non-bold) is at least 150%? What if they want to know in
pixels? I saw a chart that said that 18 point is equivalent to 24 pixels.
Does it depend on the ppi of displays and monitors that we support?

Thanks,
David

From: Jared Smith
Date: Mon, May 14 2012 5:04PM
Subject: Re: 1.4.3 Contrast (Minimum) - Large-scale text
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On Mon, May 14, 2012 at 4:02 PM, David Ashleydale wrote:

> For one thing, I find this odd because the recommendation for 1.4.4 Resize
> Text is to not use "fixed" font sizes like points. Is 1.4.4 still valid in
> today's web environment?

Because nearly all modern browsers these days resize pixel-based fonts
and also support page zoom, I do believe the restriction against
absolute font sizes is dated and irrelevant. See other concerns about
this requirement at http://webaim.org/blog/wcag-next/#textsizing

> For another, what's the best way to determine what "18 point" is in other
> measurement systems?

As you note, it's a bit tricky. I'm not sure I entirely understand
what WCAG is actually requiring here, but one way you can do this is
to measure the pixel text height of a particular font face at default
size (e.g., 100% or 1em). Firebug provides a good way to get the pixel
size. Multiply this number by 1.2 to get the minimum "Large text" size
for bold text and multiply by 1.5 to get the minimum "Large text" size
for non-bold text. Regardless of how the text is sized in the
document, the pixel heights can be measured and compared to these
baselines.

As with all things in conformance, common sense is important. Even if
something does not meet the WCAG thresholds, if it looks like it needs
more contrast, IT DOES!

Jared

From: E.A. Draffan
Date: Tue, May 15 2012 1:27AM
Subject: Re: 1.4.3 Contrast (Minimum) - Large-scale text
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I would just like to ask the question - what happens if you want to just increase the size of the fonts rather than the pictures so you can read text more easily and increase line spacing - this has been found to be incredibly helpful for those with specific learning difficulties such as dyslexia or LD?

Zoom is often too much and leaves one with lots of scrolling in both directions not helpful if you are someone who finds text appears to jump or you are coping with what they call 'rivers of text' .

Best wishes E.A.

Mrs E.A. Draffan
ECS, University of Southampton,
Tel +44 (0)23 8059 7246
Mobile +44 (0)7976 289103
http://access.ecs.soton.ac.uk
http://www.emptech.info

From: Jared Smith
Date: Tue, May 15 2012 8:01AM
Subject: Re: 1.4.3 Contrast (Minimum) - Large-scale text
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E.A.-

You are correct - increasing the text size is very useful for many
users, from those with low vision to those with various cognitive
disabilities. In order to be optimally accessible, a page should have
an adequate default text size (something that is not required by any
accessibility guidelines I'm aware of). It should also support
user-increased text sizes. WCAG doesn't require this. It allows page
zooming to meet the text resizing requirement. And it's pretty much
impossible to not support page zoom for HTML content. This means this
requirement can generally be ignored if you're simply seeking
conformance.

I would recommend reasonable support for text sizing - that the page
maintain readability and functionality when the text size is increased
to around 150%. If users need text bigger than this, they would almost
certainly be using zoom or a screen enlarger rather than or in
addition to moderate text sizing. It would also be advisable to meet
the WCAG requirement that the page support 200% zoom (which, again, is
nearly impossible to fail for HTML content).

The point in previous messages was that using pixel font sizes rather
than relative font sizes should not be considered a failure of any
WCAG success criteria because they are treated the same when resized,
etc.

Jared