{"action":"created","issue":{"url":"https://api.github.com/repos/w3c/wcag21/issues/78","repository_url":"https://api.github.com/repos/w3c/wcag21","labels_url":"https://api.github.com/repos/w3c/wcag21/issues/78/labels{/name}","comments_url":"https://api.github.com/repos/w3c/wcag21/issues/78/comments","events_url":"https://api.github.com/repos/w3c/wcag21/issues/78/events","html_url":"https://github.com/w3c/wcag21/issues/78","id":192966685,"number":78,"title":"Adapting text - Revised 31 March 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Current versions of SC and Definitions\r\n- [SC for viewing](https://rawgit.com/w3c/wcag21/adapting-text_ISSUE-74-78-79/guidelines/sc/21/adapting-text.html) | [SC for editing](https://github.com/w3c/wcag21/blob/adapting-text_ISSUE-74-78-79/guidelines/sc/21/adapting-text.html)\r\n- [SC in full draft guideline](https://rawgit.com/w3c/wcag21/adapting-text_ISSUE-74-78-79/guidelines/#adapting-text)\r\n\r\n## <span id=\"SC_Shortname\">SC Shortname</span>\r\n\r\nAdapting text\r\n\r\n**Note**: This SC merges [79 Font Family](https://github.com/w3c/wcag21/issues/79), [78 Spacing](https://github.com/w3c/wcag21/issues/78), and [74 Text Color](https://github.com/w3c/wcag21/issues/74) as they are very similar in aim (ability to override and adapt text).\r\n\r\n## <span id=\"SC_Text\">SC Text</span>\r\n\r\nEach of the following text styles of the page can be overridden with no loss of [essential](https://www.w3.org/TR/WCAG20/#essentialdef) content or functionality.\r\n \r\n1. font family by at least one different font family\r\n2. foreground color by at least one different foreground color\r\n3. background color by at least one different background color\r\n4. line spacing (leading) to at least 1.5\r\n5. letter spacing (tracking) to at least 0.12 em\r\n6. word spacing to at least 0.16 em\r\n\r\n[Captions](https://www.w3.org/TR/WCAG20/#captionsdef) and [images of text](https://www.w3.org/TR/WCAG20/#images-of-textdef) are exempt.\r\n\r\nNOTE: The goal is that pages also work with more fonts, colors, and larger spacing than the minimums cited, but the SC is met if the \"at least\" value is met.\r\n\r\n## <span id=\"Suggested_Priority_Level\">Suggested Priority Level</span>\r\n\r\nLevel AA\r\n\r\n## <span id=\"Related_Glossary_additions_or_changes\">Related Glossary additions or changes</span>\r\n\r\nNone\r\n\r\n## <span id=\"What_Principle_and_Guideline_the_SC_falls_within.\">What Principle and Guideline the SC falls within.</span>\r\n\r\nPrinciple 1, Guideline 1.4\r\n\r\n## <span id=\"Description\">Description</span>\r\n\r\nThe intent of this Success Criterion is to help ensure that people with low vision can override font family, text colors, and spacing. People with low vision often must override author settings via user stylesheet, bookmarklet, extension or application such as [VIP-PDF Reader](http://snab.ch/en/hilfsmittel/digital-tools/the-first-pdf-reader-for-visually-impaired-people/).\r\n\r\nThis SC sets metrics for a normative testable values. Any particular user is likely to choose different values (especially font & color).\r\n\r\nThe principle is that if you override the font (with any font), the issues appear. E.g. font-icons disappear. Same for colors, the act of changing them at all will highlight most or all issues people would get from changing them to their preferred colors.\r\n\r\nLine-height, letter-spacing, and word-spacing metrics were chosen as measures based on [Research](https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/References#Spacing_for_Reading). [McLeish](http://journals.sagepub.com/doi/pdf/10.1177/0264619607075995) ran from .04 to .25 em tests (Wayne E. Dick PhD analyzed the McLeish study and translated from points). McLeish found an increasing curve in reading speed of actual materials up to .25, but it really started to flatten at .20\\. Previous studies that reported no improvement started at .5em. Right at the flat point. Hence Wayne recommends letter spacing be 0.12em, and word spacing be 0.16em for this SC.\r\n\r\n[The plan is to start testing sites](https://lists.w3.org/Archives/Public/w3c-wai-gl/2017JanMar/0418.html) with these metrics on the various user-agent tools, [primarily bookmarklets](https://www.w3.org/WAI/GL/wiki/Results_of_Bookmarklet_Tests_for_Issue_78) created specifically for this. See where problems surface. Adjust measures if needed. And then provide techniques.\r\n\r\n## <span id=\"Benefits\">Benefits</span>\r\n\r\n### <span id=\"Font_Family\">Font Family</span>\r\n\r\n> Some fonts/typefaces are more readable than others. For example, some people cannot read fonts with sub-pixel rendering...\r\n> \r\n> **User Need**: Users can change the font face (also called font family or typeface) of all text, choosing from a wide range of fonts including sans serif and serif fonts..\r\n> \r\n> Source: [Accessibility Requirements for People with Low Vision, Section 3.3.2](http://w3c.github.io/low-vision-a11y-tf/requirements.html#font)\r\n\r\n### <span id=\"Text_Color\">Text Color</span>\r\n\r\n> ...some people need low brightness, especially for backgrounds. Some people, who need low brightness for backgrounds, also need low brightness overall, and thus need low-brightness text.\r\n> \r\n> Other people need high contrast between text and background, including many older people who lose [contrast sensitivity](http://w3c.github.io/low-vision-a11y-tf/requirements.html#contrast-sensitivity) from ageing. Some read better with dark text on a light background.\r\n> \r\n> For some people, common color combinations or colors from a limited color palette work fine. For example, black text on a white background, or the inverse, with white text on a black background. Other people need to select more-specific background and text colors. For example, people, who require low brightness overall, need to select the specific background and text colors that provide sufficient contrast for them, yet not too-high brightness. Readable and optimal color combinations differ vastly among individuals, and can even vary from one individual to another, depending upon conditions such as fatigue and lighting.\r\n> \r\n> Figure 8: Web page with author-defined colors with low contrast - light background, gray text, light green headings:\r\n> \r\n> ![screen capture](https://camo.githubusercontent.com/5ba828bc3346e012d6cfb6806b3db004aa21bec6/68747470733a2f2f7777772e77332e6f72672f5741492f474c2f6c6f772d766973696f6e2d613131792d74662f77696b692f696d616765732f312f31632f45672d677261792e706e67)\r\n> \r\n> Figure 9: Web page with user style with medium contrast - brown background, tan text, headings of different dull colors:\r\n> \r\n> ![screen capture](https://camo.githubusercontent.com/17c5c643fa6499965f50ec79839e4bee6fe5ff45/68747470733a2f2f7777772e77332e6f72672f5741492f474c2f6c6f772d766973696f6e2d613131792d74662f77696b692f696d616765732f612f61372f45672d6c6f77636f6e74726173742e706e67)\r\n> \r\n> Figure 10: Web page with user style with high contrast - black background, white text, headings of different bright colors\r\n> \r\n> ![screen capture](https://camo.githubusercontent.com/4e98622779f5a95b9673d77189b284f0e0290148/68747470733a2f2f7777772e77332e6f72672f5741492f474c2f6c6f772d766973696f6e2d613131792d74662f77696b692f696d616765732f372f37622f45672d68696768636f6e74726173742e706e67)\r\n> \r\n> **User Need** - Contrast: Users can set the background color and the text color from the full color spectrum.\r\n> \r\n> Source: [Accessibility Requirements for People with Low Vision, Section 3.1.2 Text Contrast](http://w3c.github.io/low-vision-a11y-tf/requirements.html#text-contrast)\r\n\r\n### <span id=\"Spacing\">Spacing</span>\r\n\r\n> Spacing such as space between lines and space between words impacts readability.\r\n> \r\n> The space between lines in a block of text is also called leading. Some people need more space between lines to be able to read text. Line spacing also helps with tracking.\r\n> \r\n> **User Need**: Line Spacing: Users can change the line spacing (leading) for blocks of text.\r\n> \r\n> Source: [Accessibility Requirements for People with Low Vision, Section 3.4.1](http://w3c.github.io/low-vision-a11y-tf/requirements.html#line-spacing)\r\n\r\n> Some people need more space between letters to read text.\r\n> \r\n> **User Need**: Letter Spacing: Users can change the letter spacing (space between letters/characters) of blocks of text.\r\n> \r\n> Source: [Accessibility Requirements for People with Low Vision, Section 3.4.2](http://w3c.github.io/low-vision-a11y-tf/requirements.html#letter-spacing)\r\n\r\n> Some people need more space between words to read text.\r\n> \r\n> **User Need**: Word Spacing: Users can change the word spacing (space between words) of blocks of text.\r\n> \r\n> Source: [Accessibility Requirements for People with Low Vision, Section 3.4.3](http://w3c.github.io/low-vision-a11y-tf/requirements.html#word-spacing)\r\n\r\n## <span id=\"Testability\">Testability</span>\r\n\r\nUsing a bookmarklet, user stylesheet, or [VIP-PDF Reader](http://snab.ch/en/hilfsmittel/digital-tools/the-first-pdf-reader-for-visually-impaired-people/) change:\r\n\r\n1.  font family to Verdana\r\n2.  foreground and background to white on black\r\n3.  line height of all text to 1.5, letter spacing to 0.12em, and word spacing to 0.16em.\r\n\r\n### <span id=\"Expected_Results\">Expected Results</span>\r\n\r\n*   No loss of content or functionality.\r\n\r\n## <span id=\"Techniques\">Techniques</span>\r\n\r\n### <span id=\"Existing_Related_Techniques\">Existing Related Techniques</span>\r\n\r\n*   [C22: Using CSS to control visual presentation of text](https://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/C22.html)\r\n*   [C21: Specifying line spacing in CSS](https://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/C21.html)\r\n*   [C14: Using em units for font sizes](https://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/C14.html)\r\n*   [C8: Using CSS letter-spacing to control spacing within a word](https://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/C8.html)\r\n*   [SCR34: Calculating size and position in a way that scales with text size](https://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/SCR34.html)\r\n*   [G140: Separating information and structure from presentation to enable different presentations](https://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/G140.html)\r\n*   [F3: Failure of Success Criterion 1.1.1 due to using CSS to include images that convey important information](https://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/F3.html)\r\n\r\n### <span id=\"New_Techniques\">New Techniques</span>\r\n\r\n*   Allowing for override of font family (future technique)\r\n*   Allowing for override of text color (future technique)\r\n*   Allowing for override of spacing (future technique)\r\n\r\n## <span id=\"Related_Information\">Related Information</span>\r\n\r\n### <span id=\"Articles\">Articles</span>\r\n\r\n*   [Unitless line-heights](http://meyerweb.com/eric/thoughts/2006/02/08/unitless-line-heights/) - Eric A. Meyer (NB: Line height doesn't need, and probably shouldn't have, a unit because it inherits from the font size)\r\n*   [How users change colours on websites](https://accessibility.blog.gov.uk/2017/03/27/how-users-change-colours-on-websites/) - Anika Henke\r\n\r\n### <span id=\"pcomments\">Public and Member Comments</span>\r\n\r\n*   [Adapting Text is needed #153 - Scott Hollier ](https://github.com/w3c/wcag21/issues/153)\r\n*   [Microsoft Comments on Adapting Text #186](https://github.com/w3c/wcag21/issues/186)\r\n*   [Oracle comment on 1.4.15 Adapting Text #222\r\n](https://github.com/w3c/wcag21/issues/222)\r\n*   [Validity Tests #276 - Wayne Dick](https://github.com/w3c/wcag21/issues/276)\r\n\r\n### <span id=\"Research\">Research</span>\r\n\r\n*   [CSS !important Spacing Test](http://www.d.umn.edu/~lcarlson/wcagwg/tests/user_styles/important_spacing.html) - Laura Carlson\r\n*   [Line Height (leading) Research](https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/References#Leading) - LVTF\r\n*   [Letter Spacing Research](https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/References#Letter_Spacing) - LVTF\r\n*   [Word Spacing Research](https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/References#Word_Spacing) - LVTF\r\n*   [Results of Bookmarklet Tests for Issue 78](https://www.w3.org/WAI/GL/wiki/Results_of_Bookmarklet_Tests_for_Issue_78)\r\n\r\n### <span id=\"Email\">Email</span>\r\n\r\n*  [User-adaptations in SCs Thread](https://lists.w3.org/Archives/Public/w3c-wai-gl/2017JanMar/thread.html#msg841) - Alastair Campbell\r\n*   [Combine 79, 78, and 74 SCs? (was Re: Mechanism Disclaimer)](https://lists.w3.org/Archives/Public/w3c-wai-gl/2017JanMar/thread.html#msg337)\r\n*   [Issue 78 SC text  - was Re: Post-Minutes update](https://lists.w3.org/Archives/Public/public-low-vision-a11y-tf/2017Feb/thread.html#msg30) \r\n\r\n### <span id=\"Minutes\">Minutes</span>\r\n\r\n*   [AG minutes, 4 April 2017](https://www.w3.org/2017/04/04-ag-minutes.html#item06)\r\n*   [Low Vision Task Force minutes, 30 March 2017](https://www.w3.org/2017/03/30-lvtf-minutes.html#item01)\r\n*   [AG minutes, 21 March 2017](https://www.w3.org/2017/03/21-ag-minutes.html#item06)\r\n*   [Low Vision Task Force minutes, 9 February 2017](https://www.w3.org/2017/02/09-lvtf-minutes.html)\r\n*   [Low Vision Task Force minutes, 2 February 2017](https://www.w3.org/2017/02/02-lvtf-minutes.html)\r\n*   [Low Vision Task Force minutes, 26 January 2017](https://www.w3.org/2017/01/26-lvtf-minutes.html#item04)\r\n\r\n### <span id=\"GitHub\">GitHub</span>\r\n\r\n*   [Issue 74: Text Color](https://github.com/w3c/wcag21/issues/74)\r\n*   [Issue 78: Spacing](https://github.com/w3c/wcag21/issues/78)\r\n*   [Issue 79: Font Family](https://github.com/w3c/wcag21/issues/79)\r\n\r\n### <span id=\"Surveys\">Surveys</span>\r\n*  [Results of Questionnaire SC review April 5, 2017](https://www.w3.org/2002/09/wbs/35422/2017April5_top3/results#xq10)\r\n*  [Results of Questionnaire SC review March 14 2017](https://www.w3.org/2002/09/wbs/35422/March14SCReviews/results#xq10)\r\n*  [Results of Questionnaire SC review February 14 2017](https://www.w3.org/2002/09/wbs/35422/SC_review_Feb14_2017/results#xnew4)\r\n\r\n### <span id=\"Wiki_Pages\">Wiki Pages</span>\r\n\r\n*   [Consensus Tally for Adapting Text SC Text](https://www.w3.org/WAI/GL/wiki/Consensus_Tally_for_Adapting_Text_SC_Text) - To include or not include \"A mechanism is available\" language\r\n*   [SC Text to Combine 79, 78, 74](https://www.w3.org/WAI/GL/wiki/SC_Text_to_Combine_79,_78,_74)\r\n*   [Brainstorming Short Name Ideas for Issue 78](https://www.w3.org/WAI/GL/wiki/Brainstorming_Short_Name_Ideas_for_Issue_78)"},"comment":{"url":"https://api.github.com/repos/w3c/wcag21/issues/comments/292161456","html_url":"https://github.com/w3c/wcag21/issues/78#issuecomment-292161456","issue_url":"https://api.github.com/repos/w3c/wcag21/issues/78","id":292161456,"user":{"login":"mraccess77","id":5640755,"avatar_url":"https://avatars0.githubusercontent.com/u/5640755?v=3","gravatar_id":"","url":"https://api.github.com/users/mraccess77","html_url":"https://github.com/mraccess77","followers_url":"https://api.github.com/users/mraccess77/followers","following_url":"https://api.github.com/users/mraccess77/following{/other_user}","gists_url":"https://api.github.com/users/mraccess77/gists{/gist_id}","starred_url":"https://api.github.com/users/mraccess77/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mraccess77/subscriptions","organizations_url":"https://api.github.com/users/mraccess77/orgs","repos_url":"https://api.github.com/users/mraccess77/repos","events_url":"https://api.github.com/users/mraccess77/events{/privacy}","received_events_url":"https://api.github.com/users/mraccess77/received_events","type":"User","site_admin":false},"created_at":"2017-04-06T12:40:57Z","updated_at":"2017-04-06T12:40:57Z","body":"To address the scoping we may need to add something like we have for SC 1.4.5 \"If the technologies being used can achieve...\"   Basically for images of text we made exceptions for technology where that could not be done -- so setting up this SC the same way would allows us to only require this when technologies allow.  I know some others won't agree -- but we have a precedent from WCAG 2.0 and it means we can keep the SC."}}
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