Re: Colour contrast algorithm when black is used

That, makes sense...

Cheers,
David MacDonald



*Can**Adapt* *Solutions Inc.*

Tel:  613.235.4902

LinkedIn
<http://www.linkedin.com/in/davidmacdonald100>

twitter.com/davidmacd

GitHub <https://github.com/DavidMacDonald>

www.Can-Adapt.com <http://www.can-adapt.com/>



*  Adapting the web to all users*
*            Including those with disabilities*

If you are not the intended recipient, please review our privacy policy
<http://www.davidmacd.com/disclaimer.html>

On Mon, Aug 21, 2017 at 9:58 AM, Sailesh Panchang <
sailesh.panchang@deque.com> wrote:

> David,
> I believe something like this should go into  the Understanding doc.
> Yes there is an algorithm that helps one to assess more objectively
> and come up with an UI that is accessible mostly but one should not
> forget that WCAG 2.0 says in the first para under introduction,
> "...they (i.e. the Guidelines) are not able to address the needs of
> people with all types, degrees, and combinations of disability".
>
> So maybe there could be a cautionary note or something noted as a
> limitation at best with an example or two culled from the emails here
> or other sources.
>
> Thanks and best wishes,
>
>
> On 8/21/17, David MacDonald <david100@sympatico.ca> wrote:
> > OK, I'm fine with that.
> >
> > I think it's important that we are having this discussion on list so that
> > we have documentation and a paper trail in response to those who may
> > criticize our 20 year old algorithm, and may be upset that we don't have
> an
> > updated algorithm for 2.1. Here's a summary of what I see:
> >
> > * The algorithm was a real win for us in WCAG 2.0 because it gave us a
> > mathematical measurement, rather than WCAG 1.0 which was fuzzy:
> >          "2.2 Ensure that foreground and background color combinations
> > provide sufficient contrast when viewed by someone having color deficits
> or
> > when viewed on a black and white screen. [Priority 2 for images,
> Priority 3
> > for text]."
> >
> > * There has never been, to our knowledge, another algorithm which has
> > superseded this one.
> > * The ugly combinations that pass WCAG that people complain about (i.e.,
> > black on dark orange) I've never seen as I've done WCAG 2 evaluations
> over
> > the last 8 years.
> > * When a new algorithm becomes available we are certainly open to vetting
> > it and incorporating it in a future version.
> >
> >
> > Does that sound right?
> >
> >
> > Cheers,
> > David MacDonald
> >
> >
> >
> > *Can**Adapt* *Solutions Inc.*
> >
> > Tel:  613.235.4902
> >
> > LinkedIn
> > <http://www.linkedin.com/in/davidmacdonald100>
> >
> > twitter.com/davidmacd
> >
> > GitHub <https://github.com/DavidMacDonald>
> >
> > www.Can-Adapt.com <http://www.can-adapt.com/>
> >
> >
> >
> > *  Adapting the web to all users*
> > *            Including those with disabilities*
> >
> > If you are not the intended recipient, please review our privacy policy
> > <http://www.davidmacd.com/disclaimer.html>
> >
> > On Mon, Aug 21, 2017 at 4:25 AM, Alastair Campbell <
> acampbell@nomensa.com>
> > wrote:
> >
> >> Hi David,
> >>
> >>
> >>
> >> I think we would be in very dangerous territory if we try and patch the
> >> algorithm without a lot more data.
> >>
> >>
> >>
> >> Just anecdotally from testing, I’ve seen at least two groups (which
> >> probably have sub-groups) who’s perception of contrast differs from
> mine:
> >> low-vision and older-people.
> >>
> >>
> >>
> >> Strong colours to my vision were muted or invisible to them, and in
> >> one-case the other way around. For example, a colleague with red/green
> >> colour blindness can read dark-blue on black easily where I can barely
> >> tell
> >> there is text there.
> >>
> >>
> >>
> >> As people (Jared, Amelia I think?) mentioned, there are differences in
> >> perception due to hue, but unless we’ve got research around the whole
> >> colour gamut for lots of different ‘vision’ types, I don’t think we
> >> should
> >> try patching the algorithm.
> >>
> >>
> >>
> >> The advantage of the hue-less algorithm is that it ‘works’ regardless of
> >> hue perception. Not perfectly, but to some degree that makes an
> >> improvement
> >> in general across groups.
> >>
> >>
> >>
> >> Cheers,
> >>
> >>
> >>
> >> -Alastair
> >>
> >>
> >>
> >>
> >>
> >> *From: *David MacDonald
> >>
> >>
> >>
> >> Could be...
> >>
> >>
> >>
> >> for a 2.1 we're probably not going to solve it all, unless we're super
> >> lucky... I'm thinking about a minor tweak from what we know now that
> >> would
> >> have broad appeal and plug significant holes.
> >>
> >>
> >>
> >> So if there's a simple amendment in a colour space, that would be
> >> awesome... I'll be interested in Jared's suggestions.
> >>
> >>
> >> Cheers,
> >> David MacDonald
> >>
> >>
> >>
> >> *Can**Adapt* *Solutions Inc.*
> >>
> >> Tel:  613.235.4902 <(613)%20235-4902>
> >>
> >> LinkedIn
> >> <http://www.linkedin.com/in/davidmacdonald100>
> >>
> >> twitter.com/davidmacd
> >>
> >> GitHub <https://github.com/DavidMacDonald>
> >>
> >> www.Can-Adapt.com <http://www.can-adapt.com/>
> >>
> >>
> >>
> >> *  Adapting the web to all users*
> >>
> >> *            Including those with disabilities*
> >>
> >>
> >>
> >> If you are not the intended recipient, please review our privacy policy
> >> <http://www.davidmacd.com/disclaimer.html>
> >>
> >>
> >>
> >> On Sun, Aug 20, 2017 at 1:10 PM, Patrick H. Lauke
> >> <redux@splintered.co.uk>
> >> wrote:
> >>
> >> On 20/08/2017 11:41, David MacDonald wrote:
> >>
> >> There recently was a Twitter discussion about colour contrast
> >> combinations.
> >>
> >> https://twitter.com/davidmacd/status/899215930445754368
> >>
> >> There seems to be consensus from stakeholders that when black #000000 is
> >> contrasted against some colours, the 4.5 threshold is met even when it's
> >> hard to see. I've noticed this for years, and it seems others have too,
> >> but
> >> the Twitter discussion got me thinking about it again.
> >>
> >> Black against #777777 passes, and black against dark orange passes, but
> >> to
> >> the eye, white #FFFFFF which fails, seems much more readable against
> this
> >> grey  or against this orange.
> >>
> >> There is something about black #000000 which needs a little tweak in the
> >> algorithm.
> >>
> >> Perhaps when black is against colour spectrum X, it requires a higher
> >> contrast minimum?
> >>
> >>
> >> Are you sure it's literally *just* full #000000 black? What about
> >> #000001?
> >> My point being that it's perhaps not just about that one particular
> >> color,
> >> but more about a particular part of the spectrum / the color space used?
> >>
> >> P
> >> --
> >> Patrick H. Lauke
> >>
> >> www.splintered.co.uk | https://github.com/patrickhlauke
> >> http://flickr.com/photos/redux/ | http://redux.deviantart.com
> >> twitter: @patrick_h_lauke | skype: patrick_h_lauke
> >>
> >>
> >>
> >
>
>
> --
> Sailesh Panchang
> Principal Accessibility Consultant
> Deque Systems Inc
> Phone 703-225-0380 ext 105
> Mobile: 571-344-1765
>