Guidelines and Tools

1. Exhibitions must make exhibit content accessible at multiple intellectual levels and present it through more than one sensory channel.
   • Offer a programmatic path for traveling through the exhibition.

     People with cognitive disabilities (e.g. learning disabilities, mental retardation), like most individuals, learn best from an orderly presentation. An exhibition that reveals its topic through an obvious story line, theme, or repeated element offers landmarks, repetition, and a connecting thread to follow a complex presentation.

     An instructional path can be imposed on a more free-flowing exhibition by the use of in-gallery printed handouts or an audiovisual kiosk. The route can also be presented in introductory labels or captioned photographs.

     Example: An introductory label or brochure can explain simply one or two themes that are carried through an exhibition. The label could be accompanied by a photograph-coded printed floor plan showing places where those themes are best illustrated. Photo-coded labels within the spaces can pose questions about the themes to further understanding.

   • Present information to all the senses.

     Deaf and hard-of-hearing people need audio information translated into print. People with visual impairments need printed information in audio and tactile formats. People with cognitive disabilities may need a combination of formats. Multisensory presentations provide choices for the sensory channel used and interesting repetitions of key points. Some people, however, have difficulty sorting overlapping sights and sounds. Balance noisy and quiet areas within the exhibition and isolate sound through receivers or acoustic treatments.

     Example: A history exhibition can present a captioned video with a descriptive narration on how and where a period garment was worn. Visitors can try on the garment in a nearby hands-on room with a time-appropriate mural as backdrop.

2. Exhibitions must include the experiences of people with disabilities within their content and presentation.
   • Include people with disabilities in exhibition topics, photographs, and presentations of perspectives (Fig. 1).
     Individuals with disabilities have contributed significantly to history, science, music, and art, among other areas. They are also a vital part of society. Yet rarely are they seen in the visual images, text, or general content of exhibitions.

   • Use the voice of people with disabilities.
     Many topics in today's society integrally involve people with disabilities. Yet when those topics are presented, perspectives of disabled people often are either not represented or are misrepresented by those who do not have disabilities. Invite people with disabilities to speak for themselves in exhibitions.

     Example: In an exhibition on scientific advancements, the issue of genetic engineering directly involves people with disabilities: If science can change genes carrying deafness, will that effort eradicate future generations of congenitally deaf people and, therefore, the culture of some deaf people--A deaf sociologist's perspective based on broad research of people who are deaf and hard of hearing could be presented in a video or in label text.

   • Include people with disabilities appropriately.
     Many if not most people with disabilities do not see themselves as victims deserving pity or as courageous souls overcoming great obstacles. Instead, they see themselves and want to be seen as people accomplishing daily and lifelong objectives using their own abilities. (See Fig. 1.)

   • Exhibition labels must use appropriate language
     when discussing issues related to people with disabilities (see below.)

     Use language that appropriately describes people with disabilities

     Yes	No
     People with disabilities	the handicapped, the disabled
     People who are deaf or hard of hearing	the hearing impaired, deaf-mute
     People who are blind or have low vision	the blind, the sightless
     Wheelchair users	those confined to wheelchairs, wheelchair bound
     People with mobility impairments	the crippled, the lame
     People with cognitive disabilities	the retarded, the mentally deficient
     People with mental illness	schizophrenic (as a generic) the insane
     People with learning disabilities	dyslexic (as a generic), the retarded

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1. Items in exhibitions (e.g. artifacts, graphics, props) must be visually accessible to people.
   • Mount small items (to center line) at no higher than 1015 mm (40 in.) above the floor.
     A male adult who uses a wheelchair has an average eye level of between 1090 mm (43 in.) and 1295 mm (51 in.) above the finished floor see Fig. 3). Objects placed above 1015 mm (40 in.) will be seen only from below by most seated and short viewers.

   • Design simple backdrops for items.
     Objects mounted against complex backgrounds (e.g. a vessel mounted against an enlarged photograph of an archaeological dig) are difficult to see for people with low vision and for those with figure-ground perceptual problems. (Figure- ground problems cause difficulty in sorting foreground from background. People with this disability, then, have difficulty finding, for example, their keys atop a desk covered with a variety of office objects.) Multiple objects staggered from the front to the back of a case may also cause visual clutter and foreground- background discrimination problems for some people.

   • Construct the top of a case at a maximum of 915 mm (36 in.) above the finished floor for items that are mounted flat on a pedestal or deck. For larger items, maintain the minimum case height possible.
     If the case floor is low but the glass is high, viewing the interior of a bowl or the overall design of a textile is blocked for both visitors with visual and mobility impairments. The standing visitor with low vision cannot get close enough to the object to see the details; the seated visitor cannot see the object's top or interior at all. Shallow cases better serve both types of visitors (see Fig. 6).

   • Construct exhibition barriers (e.g. railings) at a maximum height of 915 mm (36 in.).
     Items placed below an average-height exhibit barrier (1065 mm; 42 in.) cannot be seen by people who are short or seated. However, caution must be used when placing objects inside spaces protected by barriers. Items mounted immediately inside the barriers, if the barriers are label rails, cannot be seen over the tops of the angled labels.

   • Create color contrast between the items and the background, particularly when the items are displayed in lower light levels.
     Objects mounted in front of a solid, contrasting (color) background are most easily perceived. A 70% contrast between foreground and background is recommended. The Americans with Disabilities Act Standards for Accessible Design offers the following formula for determining contrast percentage:

     Contrast = [(B1-B2)/B1] x 100
     where B1 = light reflectance value (LRV) of the lighter area
     where B2 = light reflectance value (LRV) of the darker area

     Note that in any application both white and black are never absolute; thus B1 never equals 100 and B2 is always greater than 0.

   • Place small items in the front portion of a case, with larger items behind.
     People who have low vision often will be able to see small items that are closer.

   • Avoid shadows falling directly on items. Items placed in shadows will be lost for people with low vision.

   • When not prohibited from doing so by conservation requirements, provide at least 100 lux (10 footcandles) of light on an object.
     This is the minimum light level at which someone with low vision can see an object see Fig. 8).

   • If displaying sensitive materials that require a maximum of 50 lux (5 footcandles), then:
     • position the items to allow the visitor to approach them as closely as possible
     • light the environment with even light (i.e. do not spotlight the object and provide low-level ambient light in the gallery)
     • provide the highest contrasting background to make objects stand out in the case
     • present the objects in an alternate format, such as a reproduction or a brochure, that can be viewed in a brighter location

   • Provide photographs within an exhibition space to give accessibility to objects that require a high mounting position and/or low lighting. Laminated, high-contrast photographs, located near the individual exhibits or centrally set within the exhibition, are effective in serving those with low vision as well as those who use wheelchairs. People can hold the photographs as close as needed, at whatever angle limits glare, and in the best quality light offered within the space (see Fig. 7).

2. Items essential to the exhibition's main theme must be accessible to people by tactile examination (e.g. touching artifacts, reproduction, models) and/or comprehensive audiodescription.
   • When objects are being selected for inclusion in an exhibition, consider those that may be touched or reproduced for tactile examination.
     Tactile experiences are essential to people with visual impairments and greatly assist many people with cognitive disabilities. Tactile experiences should be included in every exhibition.

   • Select tactile objects so that they provide a coherent explanation of the exhibition topic.
     Touchable objects must be related to each other--by context and in space--in order to provide true access to exhibition content for people who have visual impairments.

     Example: In an exhibition on contemporary basketmaking, the museum chooses two or three pieces of the basketmaker's work that are examples of his most important techniques or products. The museum then includes them--or their reproductions--in the space, wherever they are appropriate for the content and design of the exhibition. It then also presents an audiodescription tour--by either an audiotape or a docent--that explains how these touchable examples relate to the others behind glass.

   • Whenever possible allow objects to be touched by all visitors, not just those who have low vision or are blind.
     Tactile access to all visitors may not always be possible (e.g. if actual works of art are used, and only limited touching by those to whom it is essential can be allowed). However, isolating individuals may embarrass those who first must identify themselves and then must handle objects in front of others. The restriction also puts an unfair burden on the guards and docents who must identify "legitimate" users. It also deprives many who could benefit by the accommodation.

   • Include touchable objects, such as models and reproductions, within the actual exhibition space.
     This allows people with visual impairments equal access to the objects without having to separate from their friends or family who are not blind or have low vision.

   • Provide audiodescription for those objects that cannot be touched or that offer little information through touch (e.g. watercolors).
     Audiodescription fills in what persons with low vision may not be able to see completely; it provides details and compares new objects to familiar ones for people who are blind. When tactile examination is possible, audiodescription can serve as a valuable complement (see Fig. 9).

3. Items must not be placed in locations such that they create a hazard to visitors.
   • Mount objects so they do not protrude more than 100 mm (4 in.) from a surface and do not present head-clearance problems.
     Objects that are wall mounted must protrude no more than 100 mm (4 in.) from the wall unless their bottom edges are cane detectable (less than 685 mm [27 in.] above the floor) (see Fig. 26) or more than 2030 mm (80 in.) above the floor.

     Objects hanging from above must have lower edges between 685 mm (27 in.) or above 2030 mm (80 in.). (See Fig. 25.) This is a critical factor when the object or work of art has features that make it dangerous.

     Example: a work of art consisting of I-beams bolted together, hanging at 1525 mm(60 in.) above the floor, is a head-clearance problem for people who are blind or have low vision or have visual-perceptual difficulties. Placing a detectable warning surface on the floor does not by itself resolve this problem. The surface must be part of a comprehensive system in the museum about which the visitor is aware. Other possible solutions are barriers around the work, a cane-detectable platform underneath the work, corridors allowing the visitor to pass without approaching the work, and a comprehensive audio-information system that alerts visitors to upcoming danger.

   • Mount objects so that they are not tripping hazards.
     Low-height (less than 305 mm (12 in.) above the floor) objects mounted on floors can be missed by people with limited fields of vision. If these objects must be floor mounted, they must be placed out of the path of circulation, be well lighted, and have a surface color of high contrast to the floor.

     Example: Mounting a work of art that is a block of aluminum 150 mm (6 in.) high on a gray carpet within a circulation corridor presents a tripping hazard to people with visual impairments. A barrier or a platform that raises the object are preferable. If those options are impossible, change the carpet color to charcoal gray, raise the general light level, spotlight the piece to create a glare off of it, and place the object's label on the other side of the corridor to draw people away from walking into the object.

   • Ensure that platforms for objects are not tripping hazards.
     Platforms should have colors that are of high contrast to the floors and walls, should not have sharp corners, and should not project unpredictably into the path of travel.

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1. Essential information in exhibition label text must be accessible to people who have difficulty reading English.
   • Avoid the use of colloquial and complex English, jargon, and technical language in text panels unless such language is explained within the text or in supplementary handouts.
     Many individuals who are deaf from birth learn English as a second language (with American Sign Language, a distinct language, being their first). Thus, a congenitally deaf person often does not comprehend the nuances of written English as a native speaker can. Information key to the story should be written in plain English.

   • Use the active voice in text panels; limit sentence label length.
     People who have difficulty reading English are most successful when the active voice is used in short sentences. Subject-verb-object sentence structure ensures better understanding. Sentence length should be no more than 25 words (15 is preferable). Label length should be a maximum of 75 to 100 words.

   • Use a line length for text that facilitates reading.
     Text containing too many characters on a line is difficult to read. Exhibit text should have a maximum of 55 characters (average) per line. Narrower columns, with 45-50 characters per line, are preferable.

   • Provide a short overview paragraph at the beginning of introductory and thematic label panels.
     People with reading difficulties as well as those with low vision tire easily from the effort of seeing and reading a great number of printed words. An overview sentence or two--set in clear, large print--allows these visitors to gather key information without having to read all of the text (see Fig. 10).

   • Carefully link sentences and paragraphs.
     Avoid pronouns that are more than a few words away from their antecedents. Try to limit a sentence or paragraph to one idea. Be sure that when making comparisons, the points of comparison are obvious.

   • Provide line drawings, silhouettes, and photographs that complement label text to aid comprehension for those with reading difficulties (see Fig. 11).

2. Label design must present main exhibition copy legibly for all visitors. Such exhibition label information must be available within the galleries in alternative formats (e.g. Braille, audio) for people who cannot read print.
   • Use typefaces that are readily legible.
     The typefaces that are easiest for people who have low vision, language problems, or cognitive disabilities are sans serif or simple serif (see Fig. 13).

     Accessible faces have the following characteristics:
     

     • proportions that contribute to legibility (see Fig. 13)
     • a clear extension for lowercase b, d, g, h, j, k, l, p, q, t, and y
     • easily legible numbers (e.g. distinguishable 5, 6, and 8)

     The following characteristics of type make reading difficult for this audience see Fig 14):

     • condensed, extended, or relatively light typefaces
     • a wide variation in stroke width
     • thin strokes that fade, break, or disappear
     • letter and numbers that closely resemble each other (e.g. the shapes of "d" and "a" or "6" and "8").

   • Do not set text in all caps.
     Type set in all caps is more difficult to read and should be limited to items such as titles and decorative heads.

   • Avoid use of script and italic type for essential information.
     These styles are inaccessible to people with low vision. Oblique type is, however, generally legible. Alternatives to italic type for book citations, artwork titles, foreign words, and quotations such as underlining, bold face, quotation marks, or another color should be used whenever possible. If an exhibition title is presented in an ornate or decorative type (and, thus, serves more as a graphic than as legible type), it should be repeated in a clearer type at an accessible location near the exhibition entrance (see Fig. 15).

   • Provide alternative forms of labels (e.g. Braille, audio, large print) within the exhibition space.
     They should be located near a well-lighted seating area in an easy-to-use format to facilitate use by visitors with visual impairments.

   • Select type size appropriate to the viewing distance.
     People who have low vision will need larger type than other visitors at every distance. Appropriate ratios type to distance are presented in Fig. 12. When calculating distance, consider also the effects of crowds on actual viewing distance. Type on signs mounted 2030 mm (80 in.) above the floor should have upper case letters at least 75 mm (3 in.) high. Minimum type size, at even the shortest distance, is an x-height of 4.5 mm (3/16 in.)

   • Provide sufficient leading.
     Leading, the space between lines (measured from baseline to baseline) should be at least 20 percent greater than the font size used. Wide column widths and typefaces with a high x-height usually require a higher ratio of type size to leading.

   • Provide consistent letterspacing and word spacing.
     Consistent spaces between letters and words facilitate reading of text passages. If kerning between letters is adjusted do not allow letters to touch each other.

   • Justify the left margin and keep a ragged right margin.
     Do not center more than three lines of label text. A predictable beginning point, line after line, and evenly spaced words are much easier to read for people with low vision and for people with cognitive disabilities. Justified text can work only if normal word and letter spacing can be preserved.

   • Provide high contrast between text and background.
     Contrast is an essential element for people with low vision. Research shows that dark on light works marginally better than light on dark for headlines. Light on dark text is acceptable for back-lit labels when light intensity is moderated (e.g. by gels) to avoid light "halo". A 70% light reflectance value contrast is most effective.

     Lighter type weight and greater letter spacing is required when type is reversed out of the background to ensure legibility.

     For outdoor signage, light type reversed out of a dark field may be desirable to offset glare.

   • Print only on a solid background.
     Overprinting (type on an imaged background) is unreadable for people with low vision and perceptual difficulties. The most minimal contrast--5% contrast to the background--overprinted with the darkest type available, may present legible text.

     Print on a surface that is textured or that has differing colors and tones (e.g. faux marble, woodgrain) can result in the same illegibility as overprinting.

   • Diminish glare on all label surfaces.
     Glare makes text unreadable for many people with low vision. Labels should be printed on eggshell, matte, or other non-glare surfaces.

   • Avoid distorting type.
     Labels should be silkscreened on clear plexiglass with another background color screened directly onto the back of the plexiglass. Clear plexiglass labels mounted on a solid surface have letter shadows that make them unreadable.

   • Mount labels so that visitors can get very close to read them.
     People with low vision often must be within 75 mm (3 in.) of a label to read it. Label and location should be situated so that the reader does not block his own light. Label location should be out of the way of barriers, protruding objects, stairs, or the swing of a door.

   • Keep in mind the natural line of sight when mounting labels.
     Labels mounted at 45 degree angles to the front of a case or vitrine are more accessible to people who have low vision than those that are mounted flat on the floor of the case. Labels should also be as close to the front of the case as possible. Labels on the back wall of a case or behind a vitrine are impossible for many people to read.

   • Define labels with color or a raised surface.
     These elements serve as clues to finding the labels for people with low vision. Type silkscreened on walls often goes undiscovered and, thus, unread by people who have low vision.

   • Mount wall labels at a height that is comfortable for both those seated and standing.
     Wall labels mounted between 1220 mm (48 in.) and 1675 mm (67 in.) are in a comfortable viewing location for both those seated and standing. Wall labels mounted with a centerline at 1370 mm (54 in.) above the floor are at optimum height for everyone (see Fig. 3).

   • Mount label rails so that the top of the label is at approximately 1015 mm (40 in.) above the floor.
     At this height the labels are low enough for those seated but not too low for people with low vision who are standing. Labels mounted lower, particularly in label wells at 305 mm (12 in.) or less above the floor, require that people who have low vision kneel to be close enough to the type.

   • Locate labels in consistent locations throughout an exhibition.
     Labels that appear in a different location at each work of art or within each case are difficult to find for people with low vision and people with cognitive disabilities.

   • Provide sufficient light to read labels.
     For text to be readable by people with low vision, lighting on the label must be between 100 lux and 300 lux (10 footcandles to 30 footcandles). (See Fig. 8.) Light must be at the same level as the light in the area immediately surrounding the label and must be uniform across the label and the rail.

   • Avoid shadows on labels.
     Shadows from nearby objects or from portions of the exhibit case lower the contrast of type to background. The possibility of shadows should be considered carefully so that text does not become illegible for people with low vision.

   Notes on 'Legibility' and 'Readability'

   Legibility and readability are different concepts. "Legibility" refers to how the design of letter forms that make up a particular font influences word recognition. Legibility contributes to "readability", or the ease of reading, which is determined by the combined impact of type size, kerning, line and word spacing, and line length.

   A particular font may evoke a certain mood or time period, but may not be very legible if used for text. For instance, a designer who wishes to display a letter in a script font to suggest it was written with a quill pen should treat the letter as an illustration, rather than as text. If the letter contains important information, a transcription in a legible font should be provided.

   Courtesy Parks Canada
   

   Design Guidelines for Media Accessibility

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