In order to do this, I am looking at Gnome Icon Themes, High Contrast, Gnome Themes Standard, and Gnome Themes Symbolic. So far, I've identified about 170 icons that I need to provide.
The purpose of the High Contrast theme is to provide the following, as outlined in Section 255 of the U.S. Telecommunications Act:
1193.43 Output, Display, and Control Functions.
All information necessary to operate and use the product, including but not limited to, text, static or dynamic images, icons, labels, sounds, or incidental operating cues, shall comply with each of the following, assessed independently:(b) Availability of visual information for low vision users. Provide visual information through at least one mode to users with visual acuity between 20/70 and 20/200 without relying on audio.
And from Section 508 of of the US Rehabilitation Act:
Subpart C - Functional Performance Criteria
1194.31 Functional Performance Criteria.
(b) At least one mode of operation and information retrieval that does not require visual acuity greater than 20/70 shall be provided in audio and enlarged print output working together or independently, or support for assistive technology used by people who are visually impaired shall be provided.
The point of the High Contrast Theme is to provide icons to users who, because of vision problems, cannot use GNOME's regular icon sets. These are users who do not use the screen reader, either:
1193.41 Input, Control, and Mechanical Functions.
Operable with Low Vision and Limited or no Hearing
1. Individuals with low vision often also have hearing disabilities, especially older individuals. These persons cannot rely solely on audio access modes commonly used by people who are blind. Tactile strategies are still quite useful, although many older persons may not be familiar with Braille. The objective, therefore, is to
maximize the number of people who can use their residual vision, combined with tactile senses, to operate a product.
2. Strategies for addressing this provision may include the following:a. Make the information on the product easier to see. Use high-contrast print symbols and visual indicators, minimize glare on the display and control surfaces, provide adequate lighting, position controls near the items they control to make them easy to find, and use Arabic instead of Roman numerals.
b. The type-face and type-spacing used can greatly effect legibility. The spacing between letters should be approximately 1/16 the height of uppercase letters and the spacing should be uniform from one label to the next. Also, symbols can sometimes be used which are much more legible and understandable than fine print.
d. A judicious use of color-coding, always redundant with other cues, is extremely helpful to persons with low vision. These cues should follow standard conventions, and can be used to reduce the need to read labels (or read labels more than the first time).
So for some of the users whose disabilities fall into the "low vision" or "partially sighted" category, color is a very helpful cue - but the catch is that it has to be a REDUNDANT cue. On of the issues that I've seen in converting the icons from the standard themes to A11y is that color is often used as a cue in the designs, but it is not always made redundant.
Some icons do, however, comply with this standard. These icons will translate more easily into the A11y theme. In the following example, the color indicates the level of charge that the battery contains. The height of the shadow in the battery also changes to indicate the same thing, which renders the color redundant:
EXAMPLE OF COLOR AS REDUNDANT CUE IN SYMBOLIC THEMEBattery-Good-Charging Icon from Symbolic Theme
Battery-Caution-Charging Icon from Symbolic Theme
High Contrast is also accessible for color blind users, and one of the easiest ways to comply with standards for that group is to present information in black and white.This section of the law defines strategies for color blind users:
Operable with Little or No Color Perception
1. Many people are unable to distinguish between certain color combinations. Others are unable to see color at all.
2. Strategies for addressing this provision include:
a. Eliminate the need for a person see color to operate the product. This does not eliminate the use of color completely but rather requires that any information essential to the operation of a product also be conveyed in some other fashion.
b. Avoid color pairs such as red/green and blue/yellow, that are indistinguishable by people with limited color perception.
c. Provide colors with different hues and intensity so that colored objects can be distinguished even on a black and white screen by their different appearance. Depending upon the product, the manufacturer may also be able to allow users to adjust colors to match their preferences and visual abilities.
d. Avoid colors with a low luminance.
So this has been my attempt to provide a basic overview of the purpose of the High Contrast Theme (as I understand it). I think that the current theme complies well with these standards, and also with the standards outlined in the Web Content Accessibility Guidelines 2.0 (WCAG 2.0). I have been getting a lot of support and help from my mentors, Andreas Nilsson and David Bolter, and also from Jakub Steiner and Lapo Calamandre. I also welcome input from anyone else who is interested in A11y and/or art. Knock on wood, by August GNOME should have a complete High Contrast Theme.