Is it possible to turn on a platform's 'increase contrast' mode when testing WCAG SC 1.4.3 Contrast (Minimum)?

[Zoey0li]

Is it possible to turn on the high - contrast mode when testing WCAG SC 1.4.3 Contrast (Minimum)? If not, then what is the function of the system's high-contrast mode? Didn't we design the high-contrast mode precisely to help people with visual impairments read the screen better?

[Zoey0li]

In addition, does the deep mode not belong to assistive technology? If I turn on the deep mode and pass the contrast test, can it also prove that the page has passed SC 1.4.3?

[patrickhlauke]

high contrast is AT that tries to override/force what an author has defined. the point of 1.4.3 is that the content itself should have sufficient contrast by itself, because not every user agent/OS has the same type of "high contrast mode" adaptations, and a user should be able to comfortably see/read content without HAVING to first jump through hoops.

[patrickhlauke]

also, no idea what "deep mode" is...

[mraccess77]

High contrast mode is there to help people who need more than a minimum level of contrast. WCAG contrast requirements are meant as a minimum level for users so that specialized accessibility features are not required. Requiring folks to use high contrast mode when they just need a little is problematic. Use of high contrast is often too much for many folks causing issues. Some browsers like Chrome don't support platform contrast settings (to my knowledge) and the Chrome contrast extension is no longer supported.

[alastc]

Initial draft response (updated in a later comment):

---

Is it possible to turn on the high - contrast mode when testing WCAG SC 1.4.3 Contrast (Minimum)?

High-contrast mode in Windows is not relevant to testing Contrast (min). The requirement is for the authored styles, rather than a user-override. (It's the same for other OSs where the mode overrides the authored styles.)

Assuming you meant "dark mode", it would depend how that is activated. If it is automatically activated then all the colour combinations must meet Contrast (min). If it is a switch provided in the site's interface then either light or dark mode could be used to meet Contrast (min).

[Zoey0li]

We are currently testing the EU's accessibility directive. The standard EN 301549 requires that mobile phone apps also comply with the requirements of the Web Content Accessibility Guidelines (WCAG). When we were testing mobile phone apps, the manufacturer informed us that it is very difficult to design a mobile phone to meet Success Criterion (SC) 1.4.3 without turning on assistive technologies such as high contrast mode. In this situation, When testing SC 1.4.3, is it also necessary to turn off the high - contrast mode?

[mraccess77]

I'm not sure why it would be harder to meet sufficient contrast on a mobile device. 1.4.3 only requires a minimal level of contrast and not a special high contrast setting based on the user platform preferences.

[scottaohara]

sounds to me like this question isn't merely about high contrast themes and how they apply to websites - but rather a device's "increase contrast" settings which has a similar purpose, but often different results/adjustments based on the platform

[mbgower]

Relevant discussion #2909 (comment)

[mbgower]

Going to leave in draft for now, in case anyone wants to review/wordsmith, given our TF discussion on Mar 28

[alastc]

Approved working group response

---

Is it possible to turn on the high - contrast mode when testing WCAG SC 1.4.3 Contrast (Minimum)?

High-contrast mode in Windows is not relevant to testing Contrast (min). The requirement is for the default styles. (It's the same for other OSs where the mode overrides the authored styles.)

For native apps, that is technically out of scope for this group. In terms of how it might be interpreted for EN 301 549 it may be similar to the previous point.

When we were testing mobile phone apps, the manufacturer informed us that it is very difficult to design a mobile phone to meet Success Criterion (SC) 1.4.3 without turning on assistive technologies such as high contrast mode.

We don't understand why it would be harder to meet contrast on a mobile app than a website. This has been added to an issue for the Mobile Accessibility Task Force to address.

[mraccess77]

@alastc when you say dark mode is activated automatically - do you mean if the platform supports dark mode and the site detects that platform setting and goes into a dark mode then the site would need to have sufficient contrast in that mode? I just want to understand that scenario. And I think we aren't saying dark mode has to be supported - but that if a site does offer dark mode and applies it automatically based on user platform settings then it would need to conform.