- From: Gregg Vanderheiden <gv@trace.wisc.edu>
- Date: Tue, 13 Dec 2005 11:04:27 -0600
- To: "'Gregg Vanderheiden'" <gv@trace.wisc.edu>, <w3c-wai-gl@w3.org>
I just went to see if we could do a comparison - and I realized we can't until we have the contrast algorithm that they propose to use with the L statistic they list at the site. It looks like this will be available in January sometime. We'll can together a comparison at that time -- although the website refers to a tool that has been developed that can be used to compare different standards. So perhaps they can use that tool to compare their algorithm with our current algorithm at the 4 end conditions (black text, black background, white text, white background) and in the middle somewhere - with various different color anomalies for the two levels (level 2 and level 3). Basically something like the text/color swatches the group used in evaluating the current rule before adopting it. The group could then compare the two approaches and see if it thinks their measure performs better. I have to say in advance that the two are similar and we could develop something that is lightness based if that is seen by the group as more desirable. You do have to introduce veiling glare which I don't see in their lightness calculation but they may have in their contrast formula (which they currently can't show us - til sometime in January). So let's sit back on this one and let them get past their conference. They can then propose something to the group for us to consider. If they can propose a specific alternate equation / criterion for our level 2 and level 3 guidelines there should still be time to consider them in January. Gregg -- ------------------------------ Gregg C Vanderheiden Ph.D. Professor - Ind. Engr. & BioMed Engr. Director - Trace R & D Center University of Wisconsin-Madison -----Original Message----- From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf Of Gregg Vanderheiden Sent: Tuesday, December 13, 2005 10:29 AM To: w3c-wai-gl@w3.org Subject: RE: CLOSED: Issue #344 Yes We looked at lightness (L) as part of our work. We found that, depending on the values you choose, you end up with comparable results to the algorithm proposed. The one we proposed however seemed to perform better at lower black end. I will forward comparisons - though it is a bit involved since they didn't specify what the threshold values should be. The key to either approach would be to define the threshold values. The link you pointed to provides an equation but no values for the threshold. Further, the tests to date have only been carried out on subjects without vision impairments. They are hypothesizing research with people who have vision deficits but there has been none to date. If we were to use this in our guidelines (which is a possibility) we would need to have values for the threshold within the next 3 months. What values would they propose for level 2 and 3? What would it be based on? Could they come up with them within the next month? Gregg -- ------------------------------ Gregg C Vanderheiden Ph.D. Professor - Ind. Engr. & BioMed Engr. Director - Trace R & D Center University of Wisconsin-Madison -----Original Message----- From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf Of Roberto Scano (IWA/HWG) Sent: Tuesday, December 13, 2005 10:05 AM To: chris.ridpath@utoronto.ca; gv@trace.wisc.edu; w3c-wai-gl@w3.org Subject: Re: CLOSED: Issue #344 Here is it: http://english.contrastocolori.org/ ----- Messaggio originale ----- Da: "Chris Ridpath"<chris.ridpath@utoronto.ca> Inviato: 13/12/05 16.45.40 A: "Roberto Scano (IWA/HWG)"<rscano@iwa-italy.org>, "gv@trace.wisc.edu"<gv@trace.wisc.edu>, "w3c-wai-gl@w3.org"<w3c-wai-gl@w3.org> Oggetto: Re: CLOSED: Issue #344 Thanks for the information. I agree with Gez that it looks sensible and promising. > Hi, there is also the italian algorithm proposed in the list. > Roberto - Sorry I couldn't find it. Could you provide a link? Cheers, Chris [Messaggio troncato. Toccare Modifica->Segna per il download per recuperare la restante parte.]
Received on Tuesday, 13 December 2005 17:04:37 UTC