Workplace Illumination – Part 10: Visual Communication

     All five human senses are used to collect information about our surroundings.  However, far more information is collected and processed by visual means than by any of the other senses.  Visual information is given higher priority than other sensory stimuli by both the structure and function of the brain.  Thus, visual communication is the dominant form of information transfer and a critical consideration in lighting system design.
     The use of color is an important element of visual communication.  As discussed in previous installments of this series, color and illumination choices are interrelated; some combinations are better enablers of effective communication than others.  This installment explores some forms of visual communication and impacts of color and lighting system design choices.

Visual Communication Methods and Applications
     Light and color are utilized in various ways to achieve effective communication.  Providing sufficient illumination to read a printed page, for example, is a basic component of visual communication; however, its scope is much broader than the choice of light sources based on luminance, CCT, CRI, and other physical parameters.  In many applications, it is the light that is viewed, rather than used to view other objects.
     Transportation vehicles provide examples of the use of light as both an aid to vision and as a visual target.  On the exterior, headlamps provide light to increase visibility of nearby objects and road surfaces forward of the vehicle.  Reversing lights serve the same function to the rear of the vehicle.  Exterior vehicle lights used as visual targets include brake lights, turn signals, and various “marker” lights.  Use of red lights is limited to the rear of a vehicle to provide a reliable indication of its direction of travel.  Taillights are maintained at moderate brightness, while brake lights are much brighter to provide a warning that the vehicle is slowing.  Turn signals blink, or flash, to attract attention and to indicate an intended direction change.  Though it employs a simple lighting scheme, a vehicle’s exterior conveys a substantial amount of information about its size, direction of travel, and changes in velocity.
     In a vehicle’s interior, entry lighting, map lights, and lights in storage areas (e.g. glovebox, console) aid passengers’ vision.  The driver’s vision is also aided by backlighting of the instrument panel and important controls.  Many lights are used as targets of a driver’s sight; fortunately, most are not presented simultaneously.  Many warning lights exist in modern vehicles, including the infamous “check engine” light, low tire pressure, and low oil pressure warnings.  Warnings of pending catastrophic failures, such as low oil pressure, are typically displayed in red, while those of lower severity are indicated in amber.  Some may blink to attract attention, such as the “fasten seat belt” admonishment; this example is also accompanied by an audible warning (beep or buzz).  Redundancy of audible and visible signals was introduced in “Occupational Soundscapes – Part 10:  Communication Systems” [6Mar2024] to overcome high-intensity noise; in this example, redundancy is employed to maximize salience in all conditions.
     Aviation, rail, and marine applications also provide familiar examples.  Airfield lights differentiate runways and taxiways for approaching pilots and increase visibility in adverse conditions.  Red- and green-lighted buoys are often used as channel markers, allowing boat captains to identify a safe route into a harbor.  A pair of red lights, flashing alternately, identifies a crossing and warns of an approaching train.
     The various forms of transportation provide a plethora of examples of light used in visual communication, but its applicability extends far beyond this realm.  Other forms of visual communication are also used; broad familiarity with various modes of transport provides a convenient source of examples that will continue to be exploited.

     Signs are also common elements of visual communication.  In addition to text, color, symbols, and other graphic elements are used to increase the efficacy of signs as communication media.
     Traffic control and warning signs are ubiquitous on public highways, varying in size, shape, color, and content to facilitate rapid transfer of information.  Large green signs, mounted above travel lanes, provide route information, primarily with text.  Moderately-sized signs are posted along roadsides to convey various information.  Red signs, such as octagonal stop and triangular yield signs, inform drivers of traffic control requirements.  Yellow signs, often diamond-shaped, convey warnings or recommendations, such as reduced speeds in curves.  A blue and white rectangular sign, with a large “H” as its focal point, guides drivers to a nearby hospital.  White and black signs are used to post speed limits and other traffic-flow information.  Orange signs inform drivers of detours, construction zones, or other special circumstances.  Many signs are standardized, usually at the federal level, to ensure consistent presentation, preventing confusion of travelers.
     The U.S. Coast Guard (USCG) standardizes signs, signals, and procedures used in navigable waterways in the U.S.  It also coordinates with other maritime agencies worldwide to ensure safe transportation in international waters.  The USCG publishes various manuals and visual reference guides to the signs, lights, and sounds used for nautical navigation.

     Standardized symbols are also important components of visual communication.  A demonstration of the power of standardized symbols was provided in “Commercial Cartography – Vol. V:  Hazard Mapping” [12Jan2022].  Consistent presentation allows rapid transfer of vast amounts of information because no additional explanation or clarification of symbols is needed for accurate interpretation of intended messages.  This can be achieved with little to no text, increasing the speed at which the information can be assimilated.

     Many of the examples of lights and signs cited thus far are fixed in location and content of the messages they can convey.  Flags, signboards, and hand signals provide flexibility in messaging; these can be used individually or in combination to create desired messages.
     Hand signals, augmented by self-luminous torches when conditions warrant, guide aircraft pilots in commercial terminals and on the decks of aircraft carriers.  The signaler is mobile at all times, allowing both the location and content of messages to be adapted as circumstances change.
     All three of the methods mentioned can be seen in use in motorsports.  A racer’s crew may display a pit board with a brief message as the racer passes.  Around the course, racers receive messages from marshals via flags.  The color and motion of a flag conveys a specific message about conditions on the race course.  Given that motorsports events are often very loud, hand signals provide a convenient method of communication among marshals.
     Another setting in which hand signals play a critical role in safety and efficient operation is a construction site, or any scenario in which rigging equipment is in use.  Verbal communication is often made impossible by distance and ambient noise created by the equipment in use or other necessary activities taking place nearby.  A standard vocabulary of signals conveys to an equipment operator when it is safe to move forward or back, raise or lower a load, and so on.  Without the coordination enabled by such visual communication, these sites and activities would be much more dangerous and much less productive.

     Nonverbal communication, as typically conceived, includes the facial expressions and body language of a person engaged in an interaction with another.  Though these cues are processed visually, they are not typically considered components of visual communication.  The term is typically used to describe prescribed messages in designed formats, transmitted with clarity and intent.  The undefined, often unintentional, nature of nonverbal communication creates only a peripheral relation to visual communication.

Theories of Visual Communication
     Several theories have been developed to explain the mechanisms and effectiveness of visual communication.  Among them are theories of perception, representation, reception, cognition, and semiotics.  A brief description of each is provided below.
     Perception theory contends that all visual communication has a neurological basis.  Vision occurs within the brain and our emotional responses dominate those driven by reason.  For example, a startling noise triggers an emotional fight-or-flight-type response, inducing physiological preparations, before the “rational brain” can assess the threat.
     Representation theory treats an image as a substitute for a real object.  Viewing an image, such as a photograph, invokes the same response as an encounter with the represented item.
     Reception theory is concerned with how visual elements convey a message, but is unconcerned with what meaning is derived from it.  This can include the use of color, symbols, or cultural references that create meaning in accordance with the message context.
     The theory of visual cognition establishes visual primacy, the dominance of vision or its prioritization over other sensory inputs.  Three evidentiary assertions support the primacy of vision:

• The brain contains regions specializing in visual processing.
• Visual processing occurs at higher speed than that of verbal stimuli.
• When verbal and visual stimuli are incongruent, the verbal input is ignored.

     The theory of visual semiotics is concerned with how the meanings of visual images are interpreted.  Generically, semiotics is “the science of signs” or the study of signs and symbols.  Its scope is broad, encompassing graphical images, physical gestures, and text and their intersections with culture and technology.
     This list of visual communication theories is not comprehensive, nor are the descriptions thorough; there is extensive literature for those interested in gaining a deeper understanding of these, or other, theories.  The objective of this brief introduction is to increase awareness of the various perspectives that can be taken with respect to any visual communication.  Awareness serves to improve the design of messages and media to maximize efficacy of visual communication for its intended audience and in unique contexts.

Recommendations
     The following is a selection of recommendations for implementation of visual communication in the workplace.  These recommendations specifically target improved safety and productivity in commercial operations; they may be less appropriate in other settings and should not be considered universal rules.

• Increase size of visual target to compensate for its distance from viewer.  For example, a person whose tasks require substantial mobility may require a larger target to be visible at the furthest points in the workspace.  Balance this with the message’s priority, ensuring that critical signals are easily detected among less-urgent information.
• Increase luminance contrast to improve visibility of visual targets, especially for workers of advanced age.  Luminance contrast is analogous to S/N for audible signals (see “Occupational Soundscapes – Part 9:  Concepts in Communication” [7Feb2024]), where the visual target is the signal and its background is the noise.
• When using hand signals or gestures, exaggerate movements to increase visibility and clarity.  Gestures made in front of the body are often difficult to see; gesture to the side whenever feasible.  Torches and high-visibility gloves are simple additions that can be used to enhance visibility of hand signals.
• Maximize use of standardized signs, symbols, and light signals.  Limit text, to the extent possible, to special situations (e.g. not covered by standardized information) that can accommodate the additional processing time required to assimilate the information.
• Minimize glare, particularly in areas where safety-critical operations are conducted.  Glare is akin to masking of audible signals (see “Occupational Soundscapes – Part 9”).  While auditory masking is frequency-dependent, the effect of glare is intensity-dependent; however, both create the potential for a signal to become imperceptible as a consequence of competing sensory inputs.
  
• Use redundant (e.g. visual + audible) signals for critical information.  This is particularly helpful when one’s tasks require mobility that removes the visual signal from his/her field of view for any length of time.
• Use intermittent (i.e. flashing) signals to attract attention to an urgent message in a “busy” visual field.
• Use a constant signal when additional information is contained within the signal, such as a symbol or text that must be properly identified.
• Combine intermittent and constant signals to maximize efficacy of communication.  For example, two signals can be used; one flashing to draw attention, one constant to convey the core message.  These functions can also be combined in a single indicator by flashing for a period, then remaining constant for a period.
• Use contrasting colors to maximize visibility of messages.  Exhibit 1 shows the ten highest-contrast color pairings under white light.

• Color-code information to accelerate access.  Materials, process steps, storage locations, and more can be identified this way to reduce errors and increase productivity.
• Test lighting and visual elements of communication to validate design assumptions; adjust accordingly.  For example, light sources with lower CRI or smaller color gamut than anticipated may warrant changes in signage to achieve desired presentation characteristics.

     This installment provides only a brief overview.  There is a great deal more to visual communication than was presented here.  The scope of this discussion is intentionally limited, endeavoring to present aspects that are readily applicable in the context of workplace lighting system design for safety and productivity without excessive exploration of tangential topics.
     The presentation of visual communication theories was kept particularly brief, foregoing detailed discussions of how each can be applied to workplace lighting and message presentation.  Application of these theories is highly context-dependent; it is more fruitful for practitioners to consider them with respect to a specific project than to discuss generalities in this already vastly-simplified presentation.
     The concepts presented here can be applied to overall plant layouts, process flows, hazard maps (see “Commercial Cartography” series), work instructions, data collection, product documentation, and so much more.  Lighting and communication in emergency situations warrants its own discussion and is the topic of a future installment.

     For additional guidance or assistance with Safety, Health, and Environmental (SHE) issues, or other Operations challenges, feel free to leave a comment, contact JayWink Solutions, or schedule an appointment.

     For a directory of “Workplace Illumination” volumes on “The Third Degree,” see Part 1:  An Introduction to Lighting (21Aug2024).
 
References
[Link] Lighting for Health and Safety.  N.A. Smith.  Butterworth-Heinemann; 2000
[Link] Human Factors in Lighting, 3ed.  Peter R. Boyce.  CRC Press; 2014.
[Link] Handbook of Visual Communication, 2ed.  Sheree Josephson, James Kelly, and Ken Smith  (eds). Taylor & Francis Group; 2020.
[Link] “Visual Communication:  Examples, Types, Elements & Importance.”  Aditya Soni.  Clearinfo.
[Link] “ANSI/IES RP-7-21 Recommended Practice: Lighting Industrial Facilities.”  ANSI.
[Link] “Visual communication.”  Wikipedia.

Jody W. Phelps, MSc, PMP®, MBA
Principal Consultant
JayWink Solutions, LLC
[email protected]