How lighting supports, enhances, destroys a retail activity

On the kitchen door of a famous contemporary London restaurant there is a notice addressed to the waiters leaving the kitchen. It says very simply: "Beyond here you are on stage". The same might be said, the other way around, of the retail environment; here the customers need to feel that the goods on show are centre stage.

One way of introducing customers to these objects of desire is through the use of lighting. The lighting designer needs to suggest to customers that this is the store that they have all been looking for.

The lighting design must make the objects of desire even more desirable, but how? How can anything like this be achieved? The answer is not simple; it requires great planning between mathematics, practicality and ultimately immaculate detail that flows through direct, indirect and interreflected lighting together with planned distinct lighting ratios.

What everyone should be aware of is that sighted people acquire 80 per cent of their knowledge of the world around them through their eyes and nowhere is this fact more relevant than in a retail store, where customers visually appraise most of the items displayed.

Even perfume needs to be packaged and presented in a visually appealing manner within an appealing environment that will attract potential customers prior to them using their sense of smell to decide on a purchase.

All this leads to the key elements in retailing, sometimes referred to as the three As - Atmosphere, Attraction, Appraisal.

The significance of the contribution that lighting can make in respect of each of these elements may be obvious but nevertheless is worth stating.

Lighting is the key element in creating a good, appropriate atmosphere, i.e. the visual ambience.

Attraction to persuade potential purchasers to inspect the merchandise is almost invariably visual - hence lighting has a significant role to play in this respect.

The appraisal of most types of merchandise is totally or partly visual. Therefore the lighting should be such to provide for accurate - possibly slightly flattering - visual appraisal that will encourage the customer to purchase.

The shop window

Whether it's facing on to the city high street or the crowded mall, the quiet courtyard or the airport departure terminal, the shop window makes a good starting point for the understanding of the role of lighting in the retail world.

This is not a case of beginning in the middle. Rather it is beginning at the edge. The shop window acts both as a frontier, separating street from retail space, and as a visual entrance, displaying the goods on sale, often allowing a visual link through into the shop itself, as well as making a statement about the type of shop it fronts.

This is not merely about the goods on sale; it is more about attitude, atmosphere and even ethos of the shop, therefore getting the light of the shop window correct is an important first step. There are a number of approaches to the great challenge that a shop window has to offer.

From the most exquisite dramatic effect of Bond's street style, where a single handbag is adorned by the latest stage lighting technology (a perfect example of centre staging) over pitch black backgrounds where the rest of the store is portrayed as a stepped discovery, to the extreme contrast of Oxford street which is busy packed with backless windows, which although are themselves an attraction leave room for the inside of the store to be discovered by the street itself.

In this case the concept describes itself, practical and descriptive. Whatever the style, from contemporary to classical, personal or impersonal attitude towards the client, expensive or cheap, whether or not the shop fits A. Van Gills matrix in any way, the lighting design of the shop window can by no means be left in any amateur's hands!

Colour

Light is a form of electromagnetic radiation, which is visible to the human eye in a narrow band between red and blue, which lie between 400 and 800 nanometres in wavelength. However, the eye's peak sensitivity is at around 590 nanometres, so we must appreciate that we ought to flatter the goods that are either at the beginning or the end of the visible spectrum for the eye to be able to appreciate them.

Colour is of great importance in retail merchandising and display; hence it is crucial that light sources of the most appropriate colour characteristics for each individual retail store are used. First consider the colour appearance needs; the cooler the appearance of the light source the "cooler" the visual ambience of the store because neutral finishes (white and grey) and the white component in pastel shades will reflect the colour appearance of the light source.

Hence it will have an effect on the colours of some merchandise as well as the interior surfaces of the store. Assuming that lamps having very good/excellent colour rendering are used - as they should - then there is a reasonable correlation between colour appearance, i.e. CCT, and the spectral power distribution, therefore the colour rendering characteristics of the light sources used.

A "warm" appearance lamp, e.g. CCT=3,000K, having very good/excellent colour rendering properties will render the reds stronger and the blues weaker than an intermediate appearance lamp, CCT=4,000K, of similar colour rendering characteristics.

Some merchandise, e.g. domestic furniture with wood finishes, is predominantly seen or assessed under artificial lighting in the home with a CCT of 2,700-3,000K and it's therefore advisable to light retail stores, or areas displaying such merchandise, with light sources having a similar CCT.

If the general lighting in the store uses lamps with a CCT of, say, 4,000K - possibly because the area includes other merchandise, such as clothing for which such lamps may be preferred - then great attention has to be paid to accent both factors equally without creating carnival out of its frame time schedule.

Illuminance - how much light is needed?

Different forms of retail outlets require different brightness ratios. Various books recommend the standard illuminance required, yet this applies only to the horizontal working planes, not vertical ones.

What I mean by horizontal working plane is the floor. Basic lighting calculations and basic computer plots can only work out how much light there will be on the floor or a given reference plane but that just does not work out for a retail outlet.

It is very rare that anyone ever questions the positions of the plane(s) in which the visual task(s) lie (the customer), and by anyone I mean those people who are very often wrongly commissioned to perform the lighting scheme of a retail outlet.

Possibly because they do not recognise the significance of this with respect to the illuminance provided by an installation or, in most cases, they do not know how to calculate for situations where the visual task is in anything other than a horizontal plane.

I very rarely walk into a shop where the merchandise is scattered on the floor; in most cases goods are either wall mounted, hung or are in vertically standing units. Then the result of such unprofessional planning is having clients messing out with the goods on display just because they can't visualise the colours correctly - and they are not to be blamed!

The practical way of designing for such situations is to determine a suitable arrangement of luminaires which, when well positioned with respect to one visual task, will provide the required illuminance.

Such an arrangement should then be installed in the position of each identified visual task on a vertical plane. This will not result in a regular arrangement of luminaires and it will be necessary to identify areas where the horizontal illuminance may be insufficient, for safety or other needs, and add luminaires.

"Good" lighting makes that object of desire more desirable - in a shop window, in a display case, on a shelf, and that's the excitement of retail lighting. Every retail environment deserves the care and attention of a professional lighting designer because, after all, I have never encountered a retailer wishing to see his/her sales on the decrease.

Ms Calleja, ELDA, LET Dip. (London) Elect. Lic A&B, is a lighting designer. She may be contacted either by e-mailing oac@di-ve.com or on 7999-5995.