In the discussion of lighting quality, there appears to be a desire to see a simplistic set of performance factors to be met, that can be universally pointed to as “quality”. This is most apparent from fixture manufacturers, who wish to have a set of 3-5 reductive bullet points to indicate their product is a “quality” product. Color rendering is one such factor frequently singled out in this effort, regardless of its relevance to an application. A quality lighting system is more than the sum of products lumped together into a specification, each defined as quality components, without contextual inter-connectivity. Lighting quality is the result of creating a recipe of approaches, priorities and understanding/agreement that delivers a system that satisfies the end-user occupants, the facility operator, and external influences to the highest practical level. To this end, I have attempted below to summarize, in the most reduced form possible, the systematic factors that define a quality design.
There is no magic formula for lighting quality.
- Quality of applied lighting approaches/systems are defined by room by room, that establish approaches to:
- Lighted spatial appearance, image, aesthetics
- Glare/brightness control
- Color selection and performance factors
- Natural and artificial light integration
- Visual performance support and enhancement
- Time and space connectivity and relationship
- Controls operation and function
- Energy use and efficiency
- Operational commitment – short and long term
- Prioritization of lighting qualities requires careful evaluation and consideration of the following considerations:
- Practical needs of those occupying spaces
- Type and character of visual tasks involved
- Human factors (demographics, condition, etc.)
- Desire to support/enhancement human health
- Sensitivity to flicker and/or color variation/distortion
- Comfort of occupants
- Available budget (energy and capital) initial and operating
- To deliver a quality lighting system/solution within the priorities and approaches defined above requires:
- Recognition that energy efficiency is not a quality of light, but it is a component of a quality lighting system
- Understanding of both the visual and non-visual effects of light on humans
- Understanding that the subjective and objective measures of quality are defined by appropriate application within established priorities and goals
- Recognition that human occupants are not singular entities that can be lumped into averaged assumptions.
- Understanding that the visual environment is a blend of objective need, subjective perception, and practical limitations that cover a broad range of requirements and perspectives.
- Realization that “lighting” quality factors must be resolved in concert with non-lighting features within spaces that enhance or detract from quality lighting in isolation.
Within each of these reduced descriptions lies a depth of detail that can be applied depending on the level of priority established. For example, for a space focused on task accuracy, consideration of human factors would require digging deeper into age range, physical condition, etc… to establish the demands on task lighting and the need for flexibility to accommodate the range of occupants anticipated. The dynamics of design may also place all of these factors in whatever order is appropriate to establish a quality end product in context to the practical definition of the project involved. In truth, the most important factor in realizing a quality solution is the quality of the approach taken and how completely it includes consideration of the range of factors, considerations and priorities involved. The more superficial an approach is, the less likely the result will be of high quality. This does not mean that quality designs need be overly complex, or time-consuming, it just means that a conscious effort to balance these considerations is what defines a quality end result.
While we might all agree that glare control is important, in some applications selecting the lowest glare product may be less important than selecting a higher efficiency product. Glare is also dependent on viewing angle and movement dynamics that cannot be universally represented by a set of features defined as “quality”, outside the context of application. High color quality is not a universal requirement – ranging from highest priority to nearly irrelevant in low demand transient occupancy. Enhancement of human visual performance can be critical in high demand tasks, yet be of minimal value in low demand transient spaces. Lighting for visual effect is meaningful for some applications, or generally irrelevant. Human factors, such as supporting visual performance, as well as mood and health enhancement factors, are naturally a component of all lighting systems designs, as lighting exists for human consumption, with no other purpose beyond this context. However, the degree of effort invested in enhancing the human experience varies greatly, from critical to merely supportive. For these reasons, and many more, lighting quality cannot be reduced to a simplistic set of universal factors, out of practical context. Lighting quality is achieved through prioritization and spatial end use delineation that establishes factors that, when met, define a quality solution and end result. The deeper one digs into the needs of end users and how light effects them, the greater the opportunity there is to create a quality experience, thus, defining a quality lighting system.