Our first priority in lighting the landscape is to provide the basic illumination that enables our vision. From there, we expand our designer’s skill to include several other goals – some obvious others more subtle. The following article not only elucidates these goals, it sets them in relation to each other. It is the relationship of lighting goals that defines lighting quality. Lighting quality is the value we bring as professional landscape lighting designers
What is Lighting Quality
Quality is a nebulous word and largely subjective. One person loves the lighting, another hates it, and another is
indifferent. With such a range of opinion, how is it possible to define and achieve this quality? The answer can be found by considering a host of factors including human needs, economics, energy efficiency, environmental issues, and considerations of architecture and plant material. The next time a homeowner asks why she should hire you to do the lighting, you will explain lighting quality and how you achieve it
A 2008 landmark publication by the IESNA, A Guide to Designing Quality Lighting for People and Buildings defines and illustrates quality lighting from a needs standpoint
۱٫ Task Visibility. Simply stated, this means providing light of sufficient brightness to see objects needed for a task. To walk on a path, you need to see the path
۲٫ Task Performance. More than just being visible, objects need to be illuminated in ways that enable us to interact with them. Steps should be lit so their risers are partly shadowed, giving us visual clues about changes in elevation.
۳٫ Mood and Atmosphere. This need encompasses our emotional responses to illuminated objects and scenes. It may seem strange to think of emotions as needs but, as lighting designers, we have more power than we can imagine – power to inspire joy, contentment, and other intangible feelings we can’t put into words
۴٫ Visual Comfort. The eye and the brain are connected by one of the most densely packed bundles of nerves in the body. Like all nerves, they are extremely sensitive to over-stimulation. Overly bright light from an unshielded filament causes real pain and disables vision momentarily. Eye fatigue is another source of discomfort and can be muscular in origin. It can result from overly dim lighting as eye muscles strain to focus and compensate for the insufficient light
۵٫ Aesthetic Judgement. Sometimes referred to as “Beauty”, the aesthetics of lighting can be described as communicating the designer’s artistic vision. This endeavor, more than all others in lighting, separates the visual artists from the average lighting installers. Designers who are able to communicate their vision of beauty with prospective clients make a visceral connection that translates into trust-based sales
۶٫ Health, Safety, and Well-Being. Lighting’s contribution to safety (safe passage throughout the property) is obvious. Less apparent are the health and well-being benefits. Well designed landscape lighting elicits feelings of security and contentment – reducing stress. Stress reduction is one of the most effective means to improve health and longevity
۷٫ Social Communication. Lighting plans should consider the needs related to human interactions. Landscape lighting designers not only light the landscape, they illuminate the people who populate it. Direct overhead lighting is very unflattering to the human face. Patio lighting that lights the periphery but leaves people in darkness does not serve the needs of the inhabitants
Summary of Quality Landscape Lighting for Human Needs
The lighting designer illuminates the landscape to serve the needs of people who live and visit there. The designer provides sufficient illumination of the right type to enable people to perform needed actions in an environment that is visible, comfortable, and aesthetically pleasing
Economics and Environment
Turtle-Safe Lighting – Florida Fish and Wildlife Conservation CommissionThe IESNA publication goes on to describe
quality lighting considering economic and environmental factors. The following points apply these factors to hardscape and landscape lighting
۸٫ Maintenance. The designer selects lighting fixtures and system components that are easily serviced and maintain integrity of the design over an extended period of time
۹٫ Ownership Cost. The designer selects energy-efficient lighting components that are reasonable in initial and ongoing cost
۱۰٫ Sustainability. The designer selects lighting components that represent responsible use of natural and man-made resources, minimize waste, maximize recycling, and minimize environmental damage
۱۱٫ Lighting Control. The designer utilizes control devices such as timers and photocells to limit energy usage while satisfying the occupants’ lighting needs
۱۲٫ Dark Sky. The designer selects lighting fixtures that minimize light pollution and light trespass
Summary of Quality Landscape Lighting for Economic and Environmental Needs
The lighting designer selects fixtures and components that are long-lived, reasonably priced, energy-efficient, and that represent a minimal impact on environmental concerns.
The IESNA document goes on to recognize the importance of architecture in lighting. The following points apply specifically to hardscape and landscape lighting issues
۱۳٫ Integration with Existing Architecture. Lighting fixtures can integrate by blending in, standing out, or complementing the architecture and hardscape. Consider lighting fixture color, texture, style, and scale; as well as fixture placement
۱۴٫ Lighting Emphasis and Variation. Lighting selectively reveals existing architectural surfaces and creates new visual impressions through selective creation of shapes and shadows. The lighting designer chooses what to illuminate and how to combine various regions of illumination to create an overall nighttime interpretation of the hardscape and architecture
۱۵٫ Codes and Standards. This point recognizes that quality includes adherence to lighting-related electrical and building codes.
Summary of Quality Landscape Lighting for Architecture
The lighting designer recognizes important architectural and hardscape features, and creates a design to selectively highlight these features. The designer also selects lighting fixtures that are visually appropriate to the surroundings.
The IESNA publication is primarily targeted towards interior lighting and street lighting so it fails to include considerations
of plant material found in the landscape. The following points should be considered as part of quality lighting design.
۱۶٫ Integration with Existing Plant Material. Lighting fixtures installed in planting beds and turf areas should blend into or complement adjacent plant material and ground cover. Plants come in a variety of colors typically referred to as earth colors – greens, blue-greens, browns, reds, and yellows. While it is not important to match fixture colors to plant colors, the most visually appealing fixtures are those in darker hues of brown, green, and bluish-green. Fixture colors that seem discordant with plants are metallic colors, black, and white
۱۷٫ Plant Growth. Lighting designers are often called upon to design and install a lighting system while plants are still immature. All plants grow, and all landscape lighting systems need to plan for this growth. Lighting designs need to include projections based on predicted plant growth. These may include installation of additional fixtures, plans to move fixtures or change lamp types. In addition, the designer should engage the homeowner in a discussion about trimming and removing plant debris from fixture surfaces
۱۸٫ Plant Health. Some horticulturists express concern about the effects of artificial illumination on plants. The concern is mainly with disruption of the plant’s light/dark cycle (responsible for growth). While some plants are more sensitive than others in this regard, there is no evidence that the low light levels in low voltage lighting cause any significant problem. A more important concern is with plants that touch or nearly touch lighting fixtures. The high level of radiant heat can damage leaves and adversely affect the health the plant. Care should be taken to position fixtures a safe distance from plants, and to prune plants as needed
۱۹٫ Plant Aesthetics. Plants are visually compelling for many reasons. One of these is that the appearance of plants changes dramatically under different types of illumination. Variations in leaf structure, translucence, reflectance, and color produce a host of visual changes that the designer can utilize. In addition, plants contribute to variety, scale, symmetry, and other lighting design qualities.
Summary of Landscape Lighting Quality for Plants
The lighting designer incorporates plant material into the lighting design with recognition of each plant’s distinctive qualities, and plans for lighting system changes as plant materials grow