RE: lvtf-ACTION-78: User settings research...

Wayne,
I agree that contrast needs to go up with smaller size text.  But from personal experience I also know that no matter how large certain text is the contrast will make it unreadable.  I’ve heard people in the field say it would be ok to allow lesser such as 1.5 contrast text if the text was 36 points or something like that.  I disagree, it’s not some linear form as you say and at some point the ability to see and distinguish the text goes out for many people even if it’s a foot high.  That is – my guess is that it is some sort of curve that falls off near the lower levels of contrast.

Jonathan

From: Wayne Dick [mailto:wayneedick@gmail.com]
Sent: Monday, September 05, 2016 2:57 PM
To: Low Vision Accessibility Task Force
Subject: Re: lvtf-ACTION-78: User settings research...

Survey of Contrast Research

Arditi and Faye [2004] performed the latest research on the decreasing relationship between font size and the level of contrast. Rubin and Legge (1989) demonstrated the need for a higher contrast threshold for people with low vision (reduced visual acuity). The discussion of contrast in Understanding SC. 1.4.3 is extremely good, except that the relationship is not as linear as implied by the presentation. Still Ariditi and Faye established that as size goes up the contrast threshold goes down. The reference to font-size guidelines from the American Printing House for the Blind were developed in a context of print material.  It is less relevant in an era of digital documents. Arditi,
Arditi, A. and Faye, E. (2004). Monocular and binocular letter contrast sensitivity and letter acuity in a diverse ophthalmologic practice. Supplement to Optometry and Vision Science, 81 (12S), 287.

Rubin GS1, Legge GE., Psychophysics of reading. VI--The role of contrast in low vision.,  Vision Research, 1989; 29(1):79-91.

APH Guidelines for Print Document Design, http://www.aph.org/research/design-guidelines/

Note: Do we need more surveys?

On Thu, Aug 25, 2016 at 8:58 AM, Low Vision Accessibility Task Force Issue Tracker <sysbot+tracker@w3.org<mailto:sysbot+tracker@w3.org>> wrote:
lvtf-ACTION-78: User settings research...

http://www.w3.org/WAI/GL/low-vision-a11y-tf/track/actions/78


Assigned to: Wayne Dick