Guidelines and Tools, part 2

1. All exhibition interactives, audio-only programs (e.g. music with lyrics and texts of speeches), and audiovisuals with soundtracks produced by the Smithsonian must be either open or closed captioned.

   If an audio presentation not produced by the Smithsonian is shown in the exhibition for more than three months it must be open or closed captioned. If an audio presentation not produced by the Smithsonian is shown for fewer than three months it may be accompanied by a verbatim script mounted directly next to it. Soundtracks of ambient sounds must be identified whether captioning or a script is used. Sounds may also be identified in label text.

   • Provide all audio narration in a print format.
     For people who are deaf or hard of hearing to understand presentations with a narrative soundtrack, they need a print translation of the narration. This print can either be open or closed captioning (for a Smithsonian production) or a verbatim transcript (allowable only for non-Smithsonian productions that are shown for fewer than three months in an exhibition space). Audio-only programs require a printed text; ambient soundtracks should be described in a label.

     Captioning is, by far, the most effective method of presenting narration in print. It allows people to watch the images and the text simultaneously. A script requires a back-and-forth effort between the screen and the script. It also requires a minimum of 16-point type, visual cuing to scenes and key points, and sufficient lighting for reading. A script is a last-resort solution. Open captioning translates the audio portion of a video or film program into visible subtitles. Viewing does not require special equipment; the captions are present on the screen at all times. Closed captioning requires a decoding capability for display on a standard television receiver and can be switched on and off by the visitor on demand.

   • For non-narrated audio programs, provide visitor-operated volume controls. People who are hard of hearing can hear music at above-average volume. Individual volume controls on hand-held audio receivers provide access to music for this audience.

2. Interactives and audiovisuals that do not have soundtracks must carry labels stating that fact to assure deaf and hard-of-hearing people that they are not missing information.

3. Audiovisual programs and computer interactives that present information with images and print must be audio described.

   Audio description (audible description of visuals fit into pauses in the soundtrack) presents information about the on-screen images and action to people with visual impairments. Provide audio description either on the general soundtrack or on a separate track accessed at the interactive site (see Fig. 9).

4. Instructions for proper use of interactives must be accessible to all visitors.
   Write instructions for interactives in a short-sentence, step-by-step format. People who have difficulty reading (e.g. some people who are deaf or who have certain learning disabilities) can perform the activities if they can get beyond the barrier of complex written instructions (see Fig. 16).

   Instructions are more effective for people with cognitive disabilities if participant action is required after each direction rather than after a string of directions. This step-action-step format assists people who have short-term memory problems.

   Add illustrations and demonstrations to support verbal instructions (see Fig. 16). Any support to the reading process can contribute to the interactive's overall effectiveness.

   Present written instructions in
   

   • 70% contrast
   • sans serif or simple serif type
   • type that has a minimum 4.5 mm (3/16 in.) x-height
   • lighting at a minimum of 100 lux (10 footcandles)

   • Present all instructions in both an audio and printed format. People who are blind and those who cannot read need instructions presented orally. Those who are deaf or hard of hearing require the instructions in print.

5. Controls for and operation of all interactives must be accessible and usable by all visitors.
   • Interactives must be within reach range of people who are short or those who use wheelchairs as well as of those who are standing.
     Locate controls (e.g. levers, buttons, track balls) so that they are within reach range of a wheelchair user and unobstructed by shelves or furniture. If the controls are to be used from a forward approach in a wheelchair, they can be no higher than 1220 mm (48 in.) and no lower than 380 mm (15 in.) above the floor (see Fig. 17). If the controls are to be used from a parallel approach, they can be no higher than 1370 mm (54 in.) and no lower than 230 mm (9 in.) above the floor (see Fig. 18).

     Some people who use wheelchairs cannot extend their arms to full length and cannot use interactives from a side approach. Front-reach range height at a maximum of 1220 mm (48 in.) above the floor is preferred (see Fig. 17a).

     Some people who are of short stature may not be able to reach controls above 915 mm (36 in.) above the floor.

   • Lower the reach height for controls that must be located over obstacles.
     To accommodate forward reach over a table top of between 510 mm to 635 mm (20 in. to 25 in.), the maximum reach height should be 1120 mm (44 in.) above the floor. (See Fig. 17b.)

     If a person using a wheelchair must make a side reach over an obstacle (of a maximum 610 mm [24 in.] depth and 865 mm [34 in.] height) to use a control, the controls can be no higher than 1170 mm (46 in.) above the floor to be usable (see Fig. 18b).

   • Eliminate glare on the interactive's instructional surfaces.
     Glare on surfaces such as a monitor screen or a plexiglass protective panel obscures viewing of the audiovisual's images and instructions for people with low vision.

   • Eliminate reflection and glare for those who are seated or short as well as for those who are standing.
     When working to redirect the negative effects of lights, it is important to consider such effects from the perspective of people who are short or seated.

   • Provide tactile characters and Braille on or directly below the controls to indicate the function of the controls unless they form a standard computer keyboard (i.e. in QWERTY format).
     Blind people and some people with low vision need tactile characters (at a 70% color contrast against their background) or Braille to identify the location and function of various controls. People with some residual vision need the markings to be in colors contrasting to the controls. A QWERTY format keyboard (where the first keys of the top line of letters are Q-W-E-R-T-Y) is universally understood and may not need additional markings.

   • Provide touch-sensitive areas in predictable locations (e.g. on all of the four corners of the screen).
     People with visual impairments or cognitive disabilities need touch screen programs that have touch areas where they can find them. This eliminates the need to run one's hand across the screen to locate the touch area, or to have to reorient oneself repeatedly to touch areas on each new screen.

   • Provide touch-sensitive areas that are at least 75 mm (3 in.) in diameter.
     Small touch areas require fine muscle control. If areas are too small, people with cerebral palsy or other mobility impairments often activate unwanted areas instead of or in addition to those selected.

   • For activities that require speaking into a specific area, provide equipment that is adjustable for height.
     In order for a wheelchair user or someone who is short to use them, manipulatives requiring a person to speak directly into them can be no higher than 1015 mm (40 in.) above the floor. If the devices are adjustable in height, people in wheelchairs who sit at different heights and people who are tall and cannot bend can use them equally well.

   • For activities that require listening at a specific area, provide equipment that is adjustable for height.
     In order for a wheelchair user or someone who is short to use them, manipulatives requiring a person to place his ear next to the object to listen can be no higher than 1017 mm (40 in.) above the floor. If the devices are adjustable in height, people in wheelchairs who sit at different heights and people who are tall and cannot bend can use them equally well.

   • For activities that require viewing in a specific area, provide equipment that is adjustable for height.
     In order for a wheelchair user or someone who is short to use them, manipulatives requiring a person to look into a specified area (e.g. a microscope) can be no higher than 915 mm (36 in.) above the floor. If the devices are adjustable in height and angle, people in wheelchairs who sit at different heights and people who are tall and cannot bend can use them equally well.

   • Prevent sound from overlapping between interactive areas.
     Some people who are hard of hearing or have difficulty filtering a lot of stimuli cannot separate foreground from background noise. For that reason, it is important that there is little overlap of sound from different sources at any one point in an exhibition. Good acoustical environments are essential.

   • Interactive elements must be operable by people who have limited muscle and hand control and by those who have only one hand. For controls and operating mechanisms to be accessible, these devices must
     
     • be fully operable with only one hand
     • require no tight grasping, pinching, or twisting of the wrist (e.g. lever handles)
     • require no more than 5 lbs. of force to operate
     • be at least 75 mm (3 in.) in their smallest dimension
     • be covered with non-slip surfaces (e.g. rubber or ridges on a trackball)

   • Provide a place to rest one's hand while using the controls.
     Some people may need additional support for hands or arms (e.g. table extension or wrist rests) in order to use controls effectively.

6. Use of interactives must be from a location accessible to people using wheelchairs or other assistive devices (e.g. canes, crutches); interactives must not be blocked by furniture or other obstacles.
   • Locate the interactive so that everyone can get to it.
     For the interactive to be accessible, it must be on an accessible route that meets all of the requirements of the Smithsonian Guidelines for Accessible Design for Facilities and Sites.

   • Provide sufficient space at and around the interactive so that everyone can use it.
     The minimum clear floor space required by a wheelchair is 760 mm (30 in.) wide by 1220 mm (48 in.) long (see Fig. 21). Therefore, a space at least that size that overlaps the accessible route is necessary in order for a wheelchair user to work at an interactive.

     Unless the activity requires only minimal interaction by the participant, that floor space must adjoin the interactive in a way that allows forward (not side) access to the activity.

     In order for the space to be usable, no more than 485 mm (19 in.) of the clear space (760 mm [30 in.] by 1220 mm [48 in.]) is under the table.

     To work at a station, a wheelchair user must have knee space at the interactive of at least 685 (27 in.) high by 760 mm (30 in.) wide by 485 mm (19 in.) deep.

     To work at a station, a wheelchair user must have the top of the work surface at between 710 mm (28 in.) and 865 mm (34 in.) above the floor.

     To make a 180 degree turn out of a station area, a wheelchair user must have either a minimum 1525-mm (60-in.) turning diameter or a 915-mm (36-in.) T-shaped area (see Fig 20).

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1. The circulation route within the exhibition must be accessible according to the requirements of the Smithsonian Guidelines for Accessible Design for Facilities and Sites.

   Create an accessible route with the following characteristics:
   To be accessible to people using wheelchairs and other mobility-oriented assistive devices, the circulation route must be at least 915 mm (36 in.) wide for one-way traffic (Fig. 22). For two-way routes, the minimum width is 1525 mm (60 in.) (Fig. 23). It is recommended that even one-way traffic routes be a minimum of 1525 mm (60 in.) to allow wheelchair users to stop to look at cases without blocking the route.

   All entrances, gates, and doors must meet accessibility requirements (e.g. width, hardware, opening force, thresholds).

   A wheelchair user's clear floor space is approximately 760 mm (30 in.) by 1220 mm (48 in.) (see Fig. 21). At least this amount of floor space is necessary on all viewing sides of exhibit cases and vitrines.

   People need to be able to get to the viewing space from the circulation route. Therefore, this clear floor space must overlap the accessible circulation route through the exhibition space.

   If a person in a wheelchair must make a turn around an obstruction, the minimum clear width of the accessible route shall be as shown in Fig. 24. Where the circulation route makes a U-turn around an object that is less than 1220 mm (48 in.) wide, the pathway width increases to at least 1065 mm (42 in.) on the approach and 1220 mm (48 in.) in the turn (see Fig. 24b).

   Where the circulation route branches off to allow viewing of cases or objects, the end of the branch provides either a minimum 1525-mm- (60-in.-) diameter circle or a 915-mm (36-in.) T-shaped turning space (see Fig. 20).

   People in wheelchairs should not have to back up out of spaces more than 915 mm (36 in.) deep, particularly crowded ones. The circle or T-shape allows someone using a wheelchair the necessary turning space to return easily to the circulation route.

   If the circulation route is less than 1525 mm (60 in.) wide, there should be passing spaces at least 1525 mm (60 in.) wide and 1525 mm (60 in.) long at reasonable intervals not exceeding 61 m (200 ft.).

   OR

   If the circulation route is less than 1525 mm (60 in.) wide, there are T-shaped intersections of two pathways--each a minimum of 915 mm (36 in.) wide--within reasonable intervals not exceeding 61 m (200 ft.).

   Clear floor spaces (approximately 760 mm [30 in.] by 1220 mm [48 in.]) should be planned to allow a person using a wheelchair to either move parallel to the case and then proceed in a forward motion or to move perpendicular to a case and then back away easily. Cases and vitrines should be positioned to avoid dead ends at walls. When this is impossible, a minimum 1525-mm- (60-in.-) diameter turnaround space must be allowed at the end. (See Fig. 20.)

   There must be at least 2030 mm (80 in.) of clear head room along the circulation route. Obstacles to be avoided include overhanging works of art, exhibit props, ceiling-mounted signs, plants, and low space under escalators. (See Fig. 25.)

   If the head room is less than 2030 mm (80 in.) in a space next to the circulation route, there is a cane-detectable barrier within 685 mm (27 in.) of the ground. This maximum height for the barrier gives someone who has low vision and using a cane the time to stop before his body hits that overhead object.

   A cane-detectable barrier can be double guardrails, large potted plants, or other solid surfaces (see Fig. 5). Stanchions with a single woven strip or a velvet rope between vertical posts are not acceptable because the horizontal barrier is above 685 mm (27 in.) and the vertical posts are too far apart to be detected in a cane sweep.

   Changes in surface texture (i.e. detectable warnings) are useful for alerting people to upcoming barriers when used in the context of an established, consistent warning system. However, they do not give sufficient warning for barriers overhead. A person using a cane will detect the change and slow his forward movement to determine the message it gives. If the cane detects nothing on the ground, the person will proceed and still hit his head on the object above. Also, dog guides do not interpret texture changes. They will proceed forward, and their masters will bump into the objects above.

   If objects mounted on the wall parallel to the pathway have bottom edges between 685 mm (27 in.) and 2030 mm (80 in.) from the floor, they must project less than 100 mm (4 in.) into the pathway. Wall-mounted objects with bottom edges below 685 mm (27 in.) may project any amount so long as they do not reduce the required minimum clear width of the circulation route (915 mm [36 in.]). This includes wall-mounted cases, wall-mounted signage that is installed perpendicular to the wall, video monitors, and other equipment that is cantilevered from the wall.

   Objects on the floor that rise less than 305 mm (12 in.), are tripping hazards. The problem worsens if the object's color does not contrast with the floor or if the lighting is poor.

   The circulation route surface must be stable, firm, and slip-resistant.

   The slope of the circulation route must be no more than 5%. If the slope exceeds 5%, then it becomes a ramp and must meet requirements for a ramp. (See ramps in the Smithsonian Guidelines for Accessible Design for Facilities and Sites.) Any cross slope (a slope that is perpendicular to the path of travel) of the circulation route must be no more than 2%.

   When circulation route levels change, the vertical difference must be less than 6.5 mm (1/4 in.). When there is a change in level of between 6.5 mm (1/4 in.) and 13 mm (1/2 in.), the edge must be beveled with a slope of 1:2. Any change greater than 13 mm (1/2 in.) must be ramped. (See Fig. 28.)

   The circulation route must be free of steps and stairs or include ramps or elevators adjacent to those steps and stairs. Ramps and elevators must meet the Smithsonian Guidelines for Accessible Design for Facilities and Sites accessibility requirements.

   If carpet or carpet tile is used on the floor, it must be securely attached.

   Carpet must have a level, low pile and a firm pad or no pad at all underneath it (maximum pile thickness is 13 mm [1/2 in.]).

   Artificial carpet surfaces and some natural surfaces (e.g. "astroturf," exterior rubber mats used to clean shoes, and cocoa mat) are extremely difficult for wheelchair users. Such surfaces cause the wheelchair wheels to pull to one side or to sink into the surface.

2. The circulation route must be clearly defined, well lighted, and easy to follow.
   • Provide sufficient lighting on circulation routes.
     A minimum of 50 to 100 lux (5 to 10 footcandles) of quality light on the circulation route is necessary for people with visual and perceptual difficulties to negotiate the path.

   • Provide nonverbal wayfinding assistance along the circulation route.
     Color coding, changes in surface texture, symbols or other nonverbal techniques assist people with cognitive disabilities in finding their way through complex environments. Color contrast (of 70%) between carpet path and edge is also an effective way to define paths for people with low vision or cognitive disabilities.

   • Visually define the walls, floors, and pedestals.
     Some people with low vision have difficulty with depth perception. Color contrast (70%) and directed lighting can differentiate horizontal from vertical surfaces on paths.

   • Design areas so that floor surfaces at and around accessible seating areas are level, stable, firm, and slip-resistant.

   • Provide an accessible floorplan to aid visitors in wayfinding.
     A floorplan that meets requirements for accessible printed and raised-line materials can assist people with visual impairments and cognitive disabilities to plan travel through complex exhibitions. These should be available at entries to exhibitions, information desks, and/or other central locations.

   • Provide more than one exit from an exhibition.
     Mid-point exits from exhibitions (particularly large exhibitions) assist those who become tired, confused, or overwhelmed when in an exhibition.

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1. All cases must provide viewing access to people who are short or seated as well as to those who are standing.
   • Design cases and pedestals so they display objects within viewing distance of people who are short, seated, or standing. (See Exhibition Items section.)

   • Design cases and vitrines so they are as shallow as possible, allowing all visitors to see objects up close and from above. (See "Exhibition Items" section.)

2. Cases and vitrines must not present a safety hazard to any visitor.
   • Design wall-mounted cases so that their lower edges are at or below 685 mm (27 in.) above the floor.
     This height allows a cane-detectable barrier for people with visual impairments (see Fig. 26). If the lower edge is maintained at 685 mm (27 in.), it also provides knee clearance for a wheelchair user who wants to move close to a case. Depending on the size of the case, a cane-detectable platform that matches the footprint of the case may work if placed on the floor directly below. This will, however, eliminate knee clearance for wheelchair users.

   • Long, horizontal cases that have legs only at the four corners (more than 305 mm [12 in.] apart) should be designed so they have a cane-detectable barrier at no higher than 685 mm (27 in.) above the floor.
     A cane user will detect objects within a sweep that extends approximately 150 mm (6 in.) to either side of his shoulders (see Fig. 27). Therefore, cases that are, for example, 1830 mm (72 in.) long with a lower edge higher than 685 mm (27 in.) could easily be hit at midsection by a person's body. Horizontal supports may provide a cane-detectable barrier.

   • Maintain a predictable border on both sides of circulation routes.
     Cases that jut unpredictably into routes--especially if the cases are not well lighted and have little color contrast to the floor and walls--are very dangerous to people with low vision. This problem is heightened if the cases have sharp angles, corners, or edges.

   • Design cases so they are distinguishable from wall openings.
     Floor-to-ceiling wall cases, with glass fronts of 1830 mm (72 in.) or more in height, can be mistaken for wall openings by people with low vision. Good case lighting, clearly defined case edges, and floors of a different material and color than the floor outside the case limit this problem.

   • Design vitrines and plexiglass barriers so they are easily detectable.
     Plexiglass and glass case tops or half-plexiglass walls in front of objects can go undetected by people with low vision. Edges and corners must be rounded. An edging of another material or even a tint at the seams and edges aids detection.

3. Seating must be provided in each exhibition. 50% of the seats must be accessible. Single-gallery exhibitions must have seating nearby, in a corridor or in an adjacent gallery space.
   • Provide accessible seating in gallery spaces.
     For seating to be accessible, seats should be firm and between 430 mm (17 in.) and 510 mm (19 in.) above the floor. Chairs or benches should have both arm and back support. This support is essential for people who have mobility impairments: arms and backs offer people support points when lowering themselves into as well as when rising out of seats. Seat backs should be firm and have an upper edge of no less than 455 mm (18 in.) above the seat; arm heights should be roughly proportionate to the back heights.

   • Provide seats that are not tripping hazards or obstacles.
     For people with low vision, seating is best located where it is not a tripping hazard and where it is clearly visible due to color contrast and good lighting. Benches should not be placed under text on walls. This presents an obstacle and a potential hazard to people who must get very close to text to read.

     Seating cannot be a barrier to people with mobility impairments. It must not block passage between areas or block the clear floor space needed to operate controls or to use equipment.

     Example: A bench cannot be placed near the latch side of door openings where people position themselves in order to open doors), below elevator buttons, or near water fountains.

   • Provide seating that can be used by people who use wheelchairs as well as by their companions.
     Benches and fixed seating need at one end a minimum 760 mm (30 in.) by 1220 mm (48 in.) space to allow a person in a wheelchair to sit next to someone on the bench (see Fig. 31) or to transfer onto the seating itself.

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1. Gallery colors (floors, walls, furniture) must create an environment that is clearly articulated, comfortable, and safe.
   • Choose colors so that floors are visually separated from the walls and furniture.
     People with low vision and visual perceptual difficulties require at least a 70% contrast in colors to negotiate a space. If the walls, floor, pedestals, and benches are all basically the same hue, all pieces of the room blend together. At minimum, contrasting baseboard strips are necessary. For floors and furniture, shadows from toekicks and glare off of metal legs provide some assistance in detection. However, furniture that is seen primarily from above (e.g. benches) will still blend with the floors unless the color contrasts.

   • Select light gallery colors if object conservation requires low lighting.
     Dark wall and floor colors absorb light. If a gallery requires low lighting for conservation reasons, the gallery colors should compensate by being light. This will counteract the low-light effects on negotiating the circulation route, seeing the objects, and reading the labels.

   • Design well-lighted spaces with limited imagery and few objects in several places within an exhibition.
     A lack of solid background in exhibit spaces forces people reading sign language to sort sign movements out of busy surroundings. This quickly becomes tiring on the reader's eyes. Well-lighted, visually quiet areas serve as respite stations for sign language tours and conversations.

2. The colors and patterns of exhibition floor surfaces must give accurate information about the depth, height, and condition of the floor surface.
   • Avoid patterned carpets and floor tiles on uneven surfaces and in low-lit areas.
     Highly patterned coverings misinform people with low vision about changing heights of the surface. This is a particular problem when the pattern is combined with pools of light and shadow or with high polish and glare. Dark colors and shadows are read as sunken; light colors and pools of light are read as raised; glare and sheen are read as wet. At minimum, more and even lighting should be provided in a gallery where patterned floors are a pre-existing condition.

3. Colors within cases must provide clear visual access to items inside.
   • Select background colors that contrast with the items in a case. (See "Exhibition Items" section.)

4. Colors for labels must have a high contrast between text and background.
   • Select label color combinations that provide sufficient contrast between print and background. (See "Label Design and Text" section.)

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