Opinion: On the skill to specify

It started with the ability to switch it on or off at the flick of a switch. Then we were able to turn it up or down by twisting a knob. Now digital LED technology enables almost any spectral power distribution to be generated; 3-D printing enables luminaires to be produced for specific luminous intensity distributions; and control systems can vary the lighting to suit time of day, season, occupancy, activity, or just peoples’ whims. The capability of lighting providers to produce systems that will perform to precisely defined specifications now far exceeds the ability of practitioners to generate specifications for intended lighting characteristics. I have for some while advocated an approach to lighting practice named the Lighting Design Objectives (LiDOs) Procedure. The lighting practitioner is guided to specify design objectives relating to the quantity and distribution of illumination for an indoor space, and from this, the procedure generates a specification for the spatial distribution of direct luminous flux to optimally achieve the objectives. The practitioner’s chosen objectives may range from efficient utilization of flux to creating a pattern of visual emphasis for selected features, and the procedure leads the practitioner to develop a spatial flux distribution that is unique to the application. This procedure is capable of being developed to incorporate a broader range of lighting design objectives. This would enable a practitioner to develop a set of objectives to describe his or her vision of how lighting is to influence the appearance of a space, its contents, and the people within it, and from this, the procedure would develop a specification that covers the spatial, spectral, and temporal distributions of flux to be provided by the luminaires. The ability to make this transition would enable not only creative designers to express their intentions with increased confidence, but also for research findings relating peoples’ responses to lighting to be readily incorporated into practice. This concept addresses a crucial issue of lighting practice. A lighting designer’s product is not beautiful lighting: it is a lighting specification that forms a basis for competitive tendering. The designer must assume that his or her solution will be installed by the contractor who has come up with the lowest price, and that this price will have been based on their estimate of the least possible amount of time being spent on site. It may also take account of their assessment of the opportunities that the specification offers for cost savings through substitutions and variation orders. The designer’s skill in firstly writing a watertight specification, and then in enforcing it, is crucial for success, but that is not new. What is new is an emerging awareness of the role that skilful specification writing can play in enabling lighting practitioners to gain full advantage of the expanding opportunities offered by our burgeoning technology.