- From: Gérard Talbot <info@gtalbot.org>
- Date: Mon, 30 Nov 2009 21:57:36 -0500
- To: "Ian Jacobs" <ij@w3.org>
- Cc: "James Hopkins" <james@idreamincode.co.uk>, "Felix Miata" <mrmazda@earthlink.net>, "www-style@w3.org" <www-style@w3.org>, "site-comments@w3.org" <site-comments@w3.org>
> It is my current understanding that > the default font size is an area of debate. Regarding CSS, accessibility, WCAG 1 and WCAG 2 (guidelines, checkpoints, techniques, examples, tips, related resources, explanations, etc), it does not seem to be an area of debate. So far, I have read many webpages coming from w3.org domain and everywhere, every single place, I read that - absolute unit for font size (like "px" and "pt") should be avoided - large fonts by default (for unstyled body content) should be provided or should be preferred - scaling font sizes smaller than the user-agent default should be avoided or should be carefully thought over Web Content Accessibility Guidelines (WCAG) 2.0 Guideline 1.4 Distinguishable: Make it easier for users to see and hear content including separating foreground from background. 1.4.4 Resize text http://www.w3.org/TR/2008/REC-WCAG20-20081211/#visual-audio-contrast-scale How to Meet WCAG 2.0 A customizable quick reference to Web Content Accessibility Guidelines 2.0 requirements (success criteria) and techniques 1.4 Distinguishable: Make it easier for users to see and hear content including separating foreground from background. Resize text 1.4.4 Sufficient Techniques for 1.4.4 - Resize text http://www.w3.org/WAI/WCAG20/quickref/#visual-audio-contrast-scale Resize text: Understanding SC 1.4.4 http://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-scale.html " When font size is specified in any absolute units of measurement, such as points or pixels, the Text Size menu commands in Internet Explorer 7 and earlier do not resize the text. " coming from C12: Using percent for font sizes http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/C12.html That is still [and also] true for Internet Explorer 8. It's not just IE7 or IE6. So that particular issue with IE will be around for 5-10 years at least. [Addendum: on top of everything, there is no minimum font-size setting which can be conveniently and quickly set in Internet Explorer 8, in Internet Explorer 7, etc.. ] " In Internet Explorer 6, using ems for font sizes will cause the text to grow more than using % or named font sizes. So, text-size/largest, might cause the text to grow more than 200% and have clipping problems. " coming from C14: Using em units for font sizes http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/C14 That is also true for Internet Explorer 7. That C14 document implicitly suggests that such bug was fixed in IE7 but it is not the case. There is another inaccuracy in C28 btw: Em units for sizes for layout container containing text will fail in a bunch of CSS columnar webpage template cases in Internet Explorer 6 and Internet Explorer 7. So, that particular example is not ideally recommendable. " Use scalable rather than absolute units. * Use em, percent(%), or keywords. Try not to use pixels (px) or points (pt) for font and block sizes because the user cannot resize them. " coming from Accessible CSS http://cookiecrook.com/AIR/2003/train/accessiblecss.php " The font size of display characters is expressed in relative size and not absolute size. " coming from Optquast Best Practice N°4 - Level 2- Section accessibility http://en.opquast.com/bonnes-pratiques/fiche/4 > On the question of color contrast, we've stuck with a grey text for > now, which I believe is WCAG 2.0 AAA compatible. G17: Ensuring that a contrast ratio of at least 7:1 exists between text (and images of text) and background behind the text http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/G17.html That page provides a list of online web applications http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/G17.html#G17-resources to test the author stylesheet and provide the "relative luminance of letters and text" algorithm. > That choice is purely > stylistic, and again, I realize it will not satisfy all users. It must be first of all a matter of compliance with G17 before it can be considered a purely stylistic issue. > Thanks for sending comments. I welcome the feedback, >From a strict demographic perspective, people over 40 or over 50 or with mild, small, average visual disabilities or mild, small, average visual loss are demographically growing proportionally speaking in the western world and their representation will be growing furthermore in the next 10-20 years. People over 40 or over 50 or with mild, small, average visual disabilities or mild, small, average visual loss are not best served by a standard body like W3C promoting an awkward "font-size: 13px" when, on the other hand, browser manufacturers all have been defaulting their browsers to "font-size: 16px" expressed in a manner that is scalable, resizable and relative in the last 15 years. >>> Is it really possible to meet WCAG 2.0 while >>> setting font sizes in px? No, it is not possible. Gérard Talbot
Received on Tuesday, 1 December 2009 02:58:19 UTC