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Re: Clarification on normative glossary definition of "Large scale (text)"

From: Ramón Corominas <listas@ramoncorominas.com>
Date: Fri, 10 Oct 2014 15:25:34 +0200
Message-ID: <5437DE4E.7020907@ramoncorominas.com>
To: "Patrick H. Lauke" <redux@splintered.co.uk>
CC: w3c-wai-ig@w3.org
I interpret this as "1.5x the base font". This would mean that, if the 
font size is too small, people with normal vision will have the same 
problems than people with visual deficiency at 1.5x sizes.

In practice, this only applies to those texts that:

a) Have a contrast ratio between 3.0:1 and 4.5:1 (or between 4.5:1 and 
7:1 if testing AAA)
b) Are larger than the body size, but seem to be close to it

In my experience those cases are not very common, but we have of course 
seen some. What we do is to compare with a "standard" font like Arial at 
14pt bold or 18pt, and basically we compare the stroke width, which is 
the most important factor in terms of contrast. Indeed, there are some 
typographies that have very thin strokes, so we apply a "correction 
factor" to them, taking into account that the Glossary notes warn about 
extremely thin fonts.


Patrick wrote:

>> *GV:  No.  Hmmm  let me try again.    18/14  point values are based on
>> the fact that the user has a screen/resolution/zoom/viewing distance
>> that makes 1em readable. *
> [...]
>> *GV:  Again. see above.       WCAG doesn’t talk about font size and
>> readability because the size of the font to the viewer is not under the
>> control of the author.  They can change RELATIVE size but the user can
>> change that with the **screen/resolution/zoom/viewing distance.     And
>> it is assumed that the viewer will use a
>> **screen/resolution/zoom/viewing distance  that works for them for the 
>> web.*
> To be clear, I am not asking with regards to readability. I am asking in 
> the context of doing a site audit and hitting that definition when 
> trying to assess contrast.
> So again, if - unless I'm misunderstanding you completely - the intent 
> of that definition was indeed to make a statement about relative size of 
> text, starting from the assumption that all factors are right for the 
> user to have a comfortable 1em size, why not make it explicit in the 
> definition and actually state this in terms of relative sizes (saying 
> "1.5x the base font size, 1.2x and bold" etc) rather than using pt 
> values? Or am I splitting hairs here?
> P

Ramón Corominas
Accessibility specialist
Technosite - Fundación ONCE
E: rcorominas@technosite.es
T: @ramoncorominas
P: +34 91 121 0330
W: http://technosite.es
Received on Friday, 10 October 2014 13:26:05 UTC

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