LVTF-Action-54

Separating Figure from Ground: Simplicity, Contrast, Polarity, Brightness
and Color

The user needs for contrast, color and brightness have been discussed on
the public-lowvision and the w3-wai-gl lists, and some gaps have been
identified. I have attempted to summarize these needs.

Simple Background: To reduce visual complexity and improve object
recognition including text and icons, the user can remove any background
images.

On w3-wai-gl removing complex backgrounds was identified as a WCAG gap by
Josh O'Connor.

Contrast: To improve visibility of foreground objects including: text,
surrounding border lines, horizontal and vertical separators and grid
lines, the user requires contrast levels that support the individual’s
perceptual requirements.

Originally we just identified text as the problem. Borders, grid lines and
other foerground objects were not included. Also contrast as a need was not
addressed alone, it was combined with color. This need separates the two.
It requires no specialized knowledge of the scientific relationship between
color and contrast to understand the user need.

Polarity: To avoid glare users may need to reverse the polarity. (Switch
from dark on light to light on dark and the reverse.)

This addresses the problem of people with sensitivity to glare who cannot
use the contrast they need without reverse polarity. We forgot this one.

Brightness: To avoid the strain caused by excess light, or loss of visual
acuity resulting from too little light, users need to control the overall
brightness of the display. This includes the ability to raise or lower the
brightness of individual objects independently within the display.

We forgot the ability to control the brightness of single objects within
the display. Dark material on a bright background can trigger photophobia
for one group and night blindness for another.

Color: To reduce reading fatigue, users need the ability to change
background and foreground colors to match the individual’s personal
preference using the full spectrum of available colors.

Color is important for people with low vision, but no legibility studies
support this. It is just that people feel better with their own colors.
Many surveys support this.

So, these are the changes to the Contrast and Brightness needs I propose.
The expansion of Contrast to include foreground objects other than text is
included.

Wayne