Re: [w3c/wcag] Proposal for color and contrast (1.3.1, 1.4.1, 1.4.3., 1.4.6, 1.4.11) (WCAG 3.0) (#901)

Hi Jim,

I just replied to him on GitHub - some of what he mentions is I think a misunderstanding of some of the functional needs of impaired, though others are certainly part of the work we are doing in Silver.

I’ve actually wanted to be on the LVTF calls to discuss some of the exciting progress going on in Silver in this regard,  but my current schedule prevents early morning calls.

I will mention that there are a couple SCs being drafted for 2.2 that refer to some of the new research (particularly that related to spatial frequency & CSF).

I hesitate with specific details as the research is ongoing, and I don't want to create misconceptions or misunderstandings. But I will tell you that small thin fonts in body text need more contrast than currently specified, and this is *for all users* not to mention those with impairments and low vision. In fact, spatial frequency is more important to CSF than luminance especially at lower contrast levels — this points to the criticality for those with contrast sensitivity issues as they have CSF curves forcing colors closer to threshold.

I’ll have some more to discuss and present to LVTF hopefully soon.


Thank you!

Andy



> On Sep 16, 2019, at 10:08 AM, Jim Allan <jimallan@tsbvi.edu> wrote:
> 
> food for thought...
> 
> ---------- Forwarded message ---------
> From: JAWS-test <notifications@github.com <mailto:notifications@github.com>>
> Date: Sun, Sep 15, 2019 at 10:52 PM
> Subject: [w3c/wcag] Proposal for color and contrast (1.3.1, 1.4.1, 1.4.3., 1.4.6, 1.4.11) (WCAG 3.0) (#901)
> To: w3c/wcag <wcag@noreply.github.com <mailto:wcag@noreply.github.com>>
> Cc: Subscribed <subscribed@noreply.github.com <mailto:subscribed@noreply.github.com>>
> 
> 
> There have been many discussions here about contrasts, which I do not think have led to a satisfactory outcome (https://github.com/w3c/wcag/issues?q=is%3Aissue+1.4.11 <https://github.com/w3c/wcag/issues?q=is%3Aissue+1.4.11>). I am afraid that the problems with WCAG 2.1 and 2.2 cannot be solved because the SCs are unchangeable and the "Understanding" documents cannot give the SCs any other meaning. But I think that for WCAG 3.0 a thorough revision of the color and contrast themes would be useful.
> 
> Unfortunately, I am not an expert in visual perception. However, I suspect that the following is correct:
> 
> Currently, color (1.4.1) and contrast requirements (1.4.3, 1.4.6, 1.4.11) overlap (#201 <https://github.com/w3c/wcag/issues/201>). This should be clearly separated.
> 1.4.11 is missing a level AAA-SC. This should be added.
> The minimum contrast of distant content is not clearly defined in any SC (#875 <https://github.com/w3c/wcag/issues/875>, #873 <https://github.com/w3c/wcag/issues/873>, #871 <https://github.com/w3c/wcag/issues/871>). This should be corrected.
> The legibility does not depend on the font size, but on the line width of the letters (i.e. the font-family and font-weight). The line width should therefore be taken into account.
> The detection of contrast distances is no better or worse for text than for non-text contents (with the same line width). 1.4.3 and 1.4.11 should therefore be merged and 1.4.6 supplemented.
> Detecting small contrast distances between foreground and background is easier than detecting small contrast distances between distant elements. 1.4.11 and 1.4.14 should therefore consider the contrast distance of distant content with a higher requirement (no exception from a certain line width).
> With distant elements the line width does not improve the detection of contrast distances. Therefore no exception from a certain line width.
> Disabled items also require minimum contrasts when submitting information (#869 <https://github.com/w3c/wcag/issues/869>). This restriction should be supplemented in the exception
> An alternative representation (e.g. text alternative instead of diagram) usually means a loss of information or efficiency for impaired users. Therefore, it should be avoided (and prohibited at level AAA).
> The contrast requirements should only apply if the user has not adjusted the contrasts. This should be added to the exception for user agents in the SC.
> If the user adjusts the colors or contrasts, he or she should still be able to perceive the information transmitted via color or contrasts (#623 <https://github.com/w3c/wcag/issues/623>). This should be covered by SC 1.3.1.
> Therefore I suggest the following:
> 
> Changed SC
> 
> 1.4.1 Use of color, Level A: Color is not used as the only visual means of conveying information.
> 1.4.3 Contrast between foreground and background (Minimum), Level AA: The visual presentation of text, images of text, user interface components and graphical objects has a contrast ratio of at least 4.5:1, except for the following:
> Wide line width: Elements with a line width greater than 2px have a contrast ratio of at least 3:1.
> Incidental: Content that is part of an inactive user interface component (unless this component transmits information), that is pure decoration, that is not visible to anyone, or that is part of a picture that contains significant other visual content, has no contrast requirement.
> Logotypes: Text and graphical objects that are part of a logo or brand name has no contrast requirement.
> User Agent and User: No contrast requirement if the appearance of the content is determined by the user agent or the user and not modified by the author.
> Alternative presentation: If there is an alternative presentation on the page that meets all requirements, then there is no contrast requirement.
> 1.4.6 Contrast between foreground and background (Enhanced), Level AAA: The visual presentation of text, images of text, user interface components and graphical objects has a contrast ratio of at least 7:1, except for the following:
> Wide line width: Elements with a line width greater than 2px have a contrast ratio of at least 4.5:1.
> Incidental: Content that is part of an inactive user interface component (unless this component transmits information), that is pure decoration, that is not visible to anyone, or that is part of a picture that contains significant other visual content, has no contrast requirement.
> Logotypes: Text and graphical objects that are part of a logo or brand name has no contrast requirement.
> User Agent and User: No contrast requirement if the appearance of the content is determined by the user agent or the user and not modified by the author.
> 1.4.11 Contrast between distant content, Level AA (Minimum): If color between distant contents (text, images of text, user interface components and graphical objects) is only visual means to communicate the status or role of the contents, the contrast ratio must be at least 4,5:1, except for the following:
> Incidental: Content that is part of an inactive user interface component (unless this component transmits information), that is pure decoration, that is not visible to anyone, or that is part of a picture that contains significant other visual content, has no contrast requirement.
> Logotypes: Text and graphical objects that are part of a logo or brand name has no contrast requirement.
> User Agent and User: No contrast requirement if the appearance of the content is determined by the user agent or the user and not modified by the author.
> Alternative presentation: If there is an alternative presentation on the page that meets all requirements, then there is no contrast requirement.
> 1.4.14 Contrast between distant content, Level AAA (Enhanced): If color between distant contents (text, images of text, user interface components and graphical objects) is only visual means to communicate the status or role of the contents, the contrast ratio must be at least 7:1, except for the following:
> Incidental: Content that is part of an inactive user interface component (unless this component transmits information), that is pure decoration, that is not visible to anyone, or that is part of a picture that contains significant other visual content, has no contrast requirement.
> Logotypes: Text and graphical objects that are part of a logo or brand name has no contrast requirement.
> User Agent and User: No contrast requirement if the appearance of the content is determined by the user agent or the user and not modified by the author.
> Note for 1.4.1, 1.4.3, 1.4.6, 1.4.11:
> This success criterion deals specifically with the perception of color/contrast in the standard display of the page. Other forms of perception are covered in SC 1.3.1 including programmatic access to information transmitted via color/contrast and other visual presentation coding.
> 
> Understanding
> 
> 1.3.1 also applies to users who adapt color and contrasts (user styles, adaptation of colours in the browser, high contrast mode etc.). This means that the following must be fulfilled for information transmitted via color or contrast:
> 
> text alternative,
> other visual means (which are not based on color and contrast) or
> programmatic access to color and contrast supported by assistive technologies (e.g. ARIA attributes are not recognized and therefore do not fulfill SC 1.3.1 for visually impaired people)
> 1.4.1 applies only to colors that transmit information as a specific color and are therefore not interchangeable (e.g. red = error, green = success). If the color is interchangeable with any other color, 1.4.1 is not applicable. Then only the contrast requirements from 1.4.3, 1.4.6, 1.4.11, 1.4.14 apply.
> 
> 1.4.3, 1.4.6
> 
> The line width of 2px corresponds approximately to the previous font size definition (14pt and 18pt).
> In order to determine the line width, the thinnest part is used whose perceptibility is relevant (for letters, for example, not the serifs).
> 1.4.11, 1.4.14 applies for example for:
> 
> focused,
> hovered,
> deactivated,
> selected,
> checked,
> faulty,
> correct,
> content type
> Relevant in this context
> 
> Note 4 in definition "contrast ratio" still relevant? #876 <https://github.com/w3c/wcag/issues/876>
> Non-sRGB color spaces, outdated sRGB threshold, and other issues in the "relative luminance" definition: #360 <https://github.com/w3c/wcag/issues/360>
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> -- 
> Jim Allan, Accessibility Coordinator
> Texas School for the Blind and Visually Impaired
> 1100 W. 45th St., Austin, Texas 78756
> voice 512.206.9315    fax: 512.206.9452 http://www.tsbvi.edu/ <http://www.tsbvi.edu/>
> "We shape our tools and thereafter our tools shape us." McLuhan, 1964