November 15, 2018

accessibility for in-gallery digital experiences, part 3 of 3

This is third and final part of a three-part series on accessibility for in-gallery digital experiences.  It was written in conjunction with my talk at the 2018 Museum Computer Network (MCN) Conference.

Recap of part 2

In identifying models for the accessibility guidelines for in-gallery digital experiences, two adjacent technologies were selected: self-service kiosks and console games. Each shares relevant characteristics with digital in-gallery experiences. Self-service kiosks have the following in common with digital in-gallery experiences: the presenter controls the environment and device and they employ a rigid user flow.  While there is no single set of standards for self-service kiosks, they do have to adhere to ADA guidelines and to the 2010 ADA Standards for Accessible Design.  Console games and digital interactives have in common rigid user flows, creative UI elements, and an issue with timing. There are at least two sets of comprehensive accessibility guidelines for games, some of which overlap with the Web Content Accessibility Guidelines (WCAG) and some of which are unique to gaming.

The Guidelines

The guidelines below aim to synthesize the lessons learned from research into the adjacent technologies of self-service kiosks and console games with the WCAG into one list that is applicable to many digital interactives.  Since digital interactives come in many forms, not every item on the checklist may be applicable to every interactive. The checklist works best when it is adapted to the specifics of the interactive.

I. Controls

  1. Physical environment meets or exceeds ADA guidelines, particularly the 2010 ADA standards for accessible design, or whatever document supersedes it  
  2. Controls are limited to tap, double tap, swipe, drag and do not require a combination of gestures
  3. Interactive elements are large and well spaced. This means:
    1. Elements are a minimum of 90 x 90 pixels on large touch screens (>980 pixels wide)
    2. Elements are a minimum of 44 x 44 pixels on small touch screens (<=980 pixels wide)
    3. Space between elements should be large enough that users can accurately target the correct elements
  4. User interface elements that are not central to the activity are stationary. Examples are menu/navigation elements; help, instructions, settings icons; and search.
  5. User is not required to repeatedly press/tap a button to participate (no button mashing)
  6. User is not required to hold a button for an extended period (>2 seconds)
  7. Activity does not rely on motion tracking of a particular body type

II. Text

  1. Font sizes are easily readable. This means:
    1. Body text is at least 16px, but a larger size may be necessary depending on the specific font and the contrast ratio
  2. Language is clear and simple. This means:
    1. Text does not require reading ability greater than lower secondary education level, which is defined by the WCAG as “the two or three year period that begins after completion of six years of school and ends nine years after the beginning of primary education”
  3. Text formatting is clear and simple. This means:
    1. Width is no more than 80 characters
    2. Line height is at least 1.5
    3. Space between paragraphs is at least 1.5 times line height
  4. Text is available in more than one language
  5. Activity includes the option to increase text size

III. Timing

  1. Users are allowed to progress through text prompts at their own pace; text prompts are dismissed on user action
  2. Precise timing is not essential to complete the activity or there is an option to disable timing
  3. There is a countdown to reset/timeout or the user is asked if they would like more time before a reset/timeout is triggered

IV. Physical Reactions

  1. Activity does not include flickering images or repetitive/flashing patterns
  2. Activity does not include any large sensory shocks (large sudden movements or sounds)

V. Orientation

  1. Activity includes instructions, guidance, and/or explanation of purpose (answers “what is this?”)
  2. Instructions, guidance, and/or explanation of purpose are available at all times
  3. Activity includes menu or navigation that is available at all times. A simplified menu (home button and prev/next pagination buttons) may be available on some screens
  4. Activity includes an indication of user’s progress through the activity

VI. Contrast

  1. Interactive elements are clearly distinguished from non-interactive elements.  This means that they are contrasted from non-interactive elements by at least two of these:
    1. Shape
    2. Color
    3. Text
    4. Movement / Animation
  2. Music/sound choices for key elements/actions/events are sufficiently distinct from each other
  3. Activity includes sufficient contrast between user interface/text and background. This means:
    1. Contrast ratio of 4:5:1 for text less than 24px
    2. Contrast ratio of 3:1 for text equal to or greater than 24px
  4. Activity includes the option to increase contrast to greater than 4:5:1

VII. Time-based Media

  1. Subtitles or captions are provided for all essential sound
  2. Subtitles or captions are provided in a clear way. This means:
    1. Text is not smaller than body text
    2. Text is presented against an opaque or semi-opaque background
    3. Text has no more than 40 characters per line
    4. Text has no more than 3 lines
  3. Activity’s background noise is kept to a minimum and can be disabled
  4. No information is conveyed by color alone
  5. No information is conveyed by sound alone
  6. All audio audio cues can be accompanied by visual cues
  7. Activity can be completed without sound
  8. Activity offers screen-reader or eyes-free mode