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Today’s technical standard allows manifold possibilities of visual advertisement with the help of artificial light, which, however, are not always fully utilized. Already at the stage of planning it should be determined which external surface for instance of business premises or of a facade comes into the question for light advertisement. In doing so, the following general conditions are to be considered:
Good recognizability
Picture and writing must appear clearly. Good recognizability is determined by the size and shape of the letters, sufficient contrast of the advertisement surface to its environment and the surrounding colours.
Selection of the right luminous colours
With the selection of luminous colours, yellow, white and green are preffared. Yellow is the most quickly sensed colour in the peripheral viewing field. Blue is the least eye-catching one. As to contrast, it is rather difficult to give generally valid recommendations for advertising installations. With wall-mounted installations, there are degrees of legibility of writings with respect to the colour of the background and the colour of the letters. Freely erected letters which have the sky as background have to be especially carefully examined as to their effect by day. For such installations, a contrast painting of two colours would be a suitable solution.
The entire advertising installation should have harmonized luminance ratios.
Luminous advertising must be effective also by day due to form and colour. Above all, it must meet aesthetical and architectural requirements.
Getting dirty must be prevented to the farest possible extent; Therefore, plane surfaces and coverings of a smooth surface finish should be used for luminous advertising. Defective parts must be easily replaceable.
It is distinguished between three types of advertising installations:
- Self-luminous installations
- Transilluminated installations
- Illuminated installations.
These include high-voltage luminescent installations and high-voltage fluorescent tube installations. They are the most common types of light advertisement and enable almost all and every form. Practically, any light colour desired can be generated by them. Light intensity is brillant and makes the installation very striking. The chief components of a fluorescent tube installation are the fluorescent tubes, the metal support in the form of relief bodies, strip or electrode boxes, the series reactors - mostly transformers - and the circuits.
The fluorescent tubes are different in thickness according to the respective purpose and size of the installation.
The total effect of an installation is determined by the relief.
The effect by night is reduced in so far as the writing can be recognized absolutely clearly only from an almost vertical direction of sight. Looked at from the side, the letters are not so well legible because they appear indistinct.
With big light advertising installations multiple illumination of the relief is necessary. The legibility of the letters can be improved by concentrating the fluorescent tubes on the cores of the letters leaving edges of 5 to 6 cm in height. The relief body and the equipment are decisive for the effect of the advertising installation by night.
All fluorescent tube writings are special constructions.
At first, a commercial artist designs the planned installation as to its effect by day and night. Starting from these drafts, drawings scaled 1:10 are made for an offer. These drawings show all technical details.
Figure 54. System structure of a
fluorescent lamp installation
1 relief body, 2 fluorescent tube, 3 steel tube, 4 earth lead, 5 protective casing, 6 isolating switch
- Lamps with cold electrodes.
- Little light efficiency due to cathode drop up to 450 V.
- Only long lamps are economical.
- Operating voltage is between 800 and 6000 V, approximately.
- Lamps without luminescent material supply a light yield between 2.5 and 5.5 lm per watt.
- High voltage is generated by leak transformer. With the help of an adjustable shunt, the high voltage is adapted to the operating parameters of the respective lamp or a number of lamps connected in series.
- Service life about 10000 hours.
The colour effects (coloured tubes) are produced with the help of
Luminescent materials
- calcium wolframate - colour light-blue
- magnesium wolframate - colour bluish-white
- zinc silicate - colour light-green
- zinc beryllium silicate - colour yellowish white
- cadmium silicate - colour yellowish white
- cadmium boaate - colour carmine
as well as by radiation of inert gas
- helium - colour whitish pink
- neon - colour orange red
- argon - colour bluish grey
- hydrogen - colour violet
- nitrogen - colour yellow
- oxygen - --
- carbon monoxide - colour white
- mercury - colour bluish grey
- sodium - colour yellow
Table 31. Characteristic values of high-voltage fluorescent lamps
|
Power |
Luminous flux |
Light colour |
Tube length |
|
(W) |
(lm) |
|
(mm) |
|
30 |
600 |
daylight white |
1000 |
|
35 |
750 |
daylight white |
1250 |
|
40 |
900 |
white |
1500 |
|
44 |
1050 |
warm tone |
1750 |
|
47 |
1200 |
special colours |
2000 |
|
50 |
1350 |
special colours |
2250 |
Figure 55. High-voltage fluorescent
lamp circuits
1 fluorescent lamp up to 3 kV and/or fluorescent letters up to 6 kV
In addition to the high-voltage fluorescent lamps - rod or letter-shaped - pertinent sockets, leak transformers are required. There are installation transformers and letter transformers. A writing can be fed by one transformer or several letter transformers. In case of failure of an installation transformer the entire writing goes out, whereas it comes to gaps between the letters if individual transformers fail to function. It is up to the user to decide about the type of transformer used.
For increasing the advertising efficiency of light installations, these can be equipped with special switching devices. The following versions are used:
- Flashing circuits with bimetallic contacts or controller drums.- Multitext circuits with which, by a motor-operated switch mechanism, the main text (by-day effect) is switched alternately with an additional text on a secondary level.
- Program circuits with controller drums, with which individual letters or words can be added to a picture.
- Shadow line switchings with which a movement is pictured on a surface by direction-oriented switching steps.
This effect is achieved by dividing the entire length of a tube in as many small uniform or equally long portions as possible, which are switched over the primary side by means of a switching mechanism.
- Polypole switching producing the impression of writing or flowing light.
It works by controller drums on the high-voltage side.
As fluorescent tubes multielectrode valves are used. The distance between the electrodes is 10 to 15 cm.
- Rotating installations are a form of free-standing advertising installations.
By rotation, the eye of the looker-on is caught by day and in the dark as well. The rotation cycles with installations of a diameter of 4 m or diagonal arrangement shall be 2 to 2.5 rotations per minute, with installations of more than 4 m 1.2 to 1.5 rotations per minute.
- Swelling-light installations with which gradual growing and decreasing of the luminous flux is enabled by actuators. The best interval of regulation between minimum and maximum values of the luminous flux has proved to be 1 s.
- Colour spreading is based on mixing the three primary colours red, green and blue in an additive way. By doing so, any other colour can be created.
The period of one colour cycle should last between 5 and 10 s.
Hints to practice
Advertising installations require specially careful installation. High-voltage advertising installations - due to the high voltages applied - are very hazardous. The use of spotlights involve the danger of fire because inflammable materials may be ignited by the focal points of the reflectors and lenses which are situated far from the spotlights themselves.
The most commonly known installations of this group are the transparents. Their effectivity depends on the condition, that the entire luminescent surface appears uniformly bright.
The coverings used must produce a good light scattering.
Flashed turbid glass or plastic material of equal scattering are the best suited coverings, whereas spotted glass has a good scattering effect but causes more loss of light.
With direct transillumination, frosted glass should not be used.
The distance of the lamps to the turbid-glass surface must not fall short of a definite measure.
If filament lamps are used, the minimum distance of the lamp from the transparent surface must amount to one third of the diagonal of the surface portion to be illuminated by the lamp.
The distance between the lamps is maximally the 1.5-fold of the distance of the lamps from the luminous area. If such distance cannot be realized, the transparent surface may be irradiated indirectly, which, however, requires much more energy. In any case, transparent boxes must get a diffuse white painting.
The important point with this type of installation is to achieve the best possible uniformity of the surface to be illuminated by direct lighting of the advertising surface. Test have shown that illumination differences of 3:1 are still perceived as uniform by the eye. Uniformity depends on the distance of the lighting fitting from the surface and from the incident angle of the light. The conditions become the better, the higher the angle of incidence is. The limit of the reflector distance from the advertising surface as to the sensation of uniformity is two thirds of the height of the surface. If this distance cannot be observed, this is to say if the distance of the reflector cannot be made smaller than half the height of the board, uniformity can be achieved by fixing a reflection strip on the lower edge. However, this can be made only with smaller surfaces.
In sales rooms, the attention of the customer is invited and wishes are awaked mainly by optical impressions. Here is a large sphere of action for lighting engineering. Generally, the following rules apply to the design of lighting installations in sales rooms:
- Illumination must be sufficiently intensive; it is determined by the degree of reflection of the goods.- If possible, the lighting installation should be mobile in order to be able to follow shifts of the focal points of sale within the sales room.
- The lighting installation must be haromized with the interior architecture of the room.
- The lighting installation must produce no disturbing glare.
- The lighting installation should be easy of access for maintenance reasons.
There are recommendations concerning the selection of lighting in sales rooms. In this context, the indications on the illumination should be considered as the minimum requirements. It is determined by two factors: the colour of the goods and the situation of the sales rooms as regards traffic. Dark coloured goods require more illumination than bright goods. If in a sales room dark ware is frequently followed by light-coloured articles or vice versa, the lighting installation should be constructed in such way that illumination is adjustable. With the selection of the light colour two things have to be considered: Firstly, the colour rendition qualities of the products sold are important and secondly, customer and shop-assistant must find themselves in a pleasant light. Therefore, fluorescent lamps of ‘neutral white’ light colour are used in most sales rooms. In many sales rooms, lighting fittings are included in the design of the inserted ceiling, especially if the rooms must be ventilated or partially air-conditioned. Many possibilities of variation are offered by modern assembly ceilings, which can easily be adapted to the changing design of the sales room and the changing lighting situation resulting therefrom. In addition to the general lighting, the equipment of a sales room must provide for additional local lighting for marking main points of sale. By illuminating an article with the help of point-shaped light sources, its plasticity and gloss can be accentuated. Make sure that glare is avoided. Direct glare is prevented by screens, reflection glare by selecting the right place of installation.
Lighting fittings that shall illuminate the counter should be placed above the front edge of the counter, so that the customer does not stand in his own light or is disturbed by reflection or a shiny table-top.
Very often, show-cases or shelves are used for display. They, too, require appropriate illumination.
For the illumination of exhibition rooms for motor vehicles luminous ceilings or indirect illumination of the room is applied.
This kind of illumination is especially suitable in cases where show-windows and sales rooms are combined. This way, a calm and uniform illumination of the entire room is achieved, and the vehicles can be viewed well from all sides.
A disadvantage consists in the low efficiency factor of the installation and the uniformity that creates no special eye appeal in the room. Luminous rows on the ceiling of the exhibition room look more gay due to the reflection of the lights by the car-bodies. However, the fittings always must be covered by opaline glass, plastic cups or spill shields. Furnishing houses, too have to be treated as a unity of show-windows and sales rooms as regards illumination. Very often, completely furnished rooms are shown including wall-paper, carpets, curtains, vases and lighting fittings. The lighting fittings should always be switched on. Because they do not supply sufficient sales room illumination, additional general lighting is required in the form of fluorescent lamps placed above the show-window pane behind the window head. These fittings have to be covered by wooden or sheet metal flashings or by spill shields, so that they are not to be seen from the sales room. In large rooms, general lighting is effected by fluorescent lamps arranged directly on the ceiling and covered by large-space spill shields or by covered lighting fittings integrated in ceiling systems. The right lighting of glass, crystal and jewellery shops is a special challenge due to the manifold refraction of light, reflection and mirror effects which attract the attention of the looker-on.
In the sales rooms of textile shops the goods must be presented to the customer not only in artificial light but also in daylight. For this purpose, try-on cabins have to be equipped with xenon lamps the spectral energy distribution of which is similar to daylight with overcast sky.
In all sales rooms where clothings are sold, mirror illumination deserves special attention. In a good mirror lighting, the entire person should appear in a uniform light without dark shadows. The best possible illumination is achieved by one light source on either side of the mirror. The lighting fitting must be such that the looker-on is not dazzled. Point-shaped light sources, as a general principle, must be placed behind light-scattering materials. Line-shaped light sources should be screened in the same way.
A special type of sales rooms are those where clothes are presented by fashion models, for instance outer garments for ladies and gentlemen. Usually, such rooms are rather comfortably furnished. Illumination must enable the customer to see all details of the clothes presented. Illumination must be free of glare, and especially vertical illumination must be sufficient.
The old advertising slogan ‘light attracts people’ applies especially to the decoration of shop-windows. With shop-window illumination, luminescent lamps are prevailing.
For achieving special effects, reflector fittings or silvered filament lamps with or without colour filter are used.
By this, individual parts of the shop-window can be accentuated.
Most articles require illumination from below, so that the construction of the shop-window should provide for the connection of additional lighting fittings near the floor.
The selection of the illumination is - similar to the sales room illumination - determined by the kind of goods exhibited in the respective show-window and by the traffic situation.
In table 32, recommended values for the illumination of shop-windows are to be found.
Recommendations for the electric power that should be available per square metre base surface of the shop-window are indicated in table 33.
Table 33. Recommended values of electric power per square metre
|
Size of settlement |
Main roads |
Boulevards |
Business streets |
| |
(power per square metre) | | |
|
50000 |
300 |
200 |
100 |
|
inhabitants |
| | |
|
50000 |
200 |
100 |
50 |
The following demands are made on shop-window lighting:
- The shop-window must have a sufficient illumination level according to the kind of articles displayed.- The goods exhibited must form a good contrast to the rear wall of the shop-window.
- If the shop-window decoration has light or dark colours alternately, the lighting installation must enable the switching-on of more or less light.
- No lamps or lighting fittings must be visible from the standpoint of the passer-by in front of the shop-window. Reflections on the rear panel of the shop-window should be avoided by using dull material in this place.
- Lamps and lighting fittings from the sales room have to be covered by shields on the rear wall of the shop-window.
- No unnatural shadows must be created; this holds especially true for things situated near the shop-window pane.
- There must be sufficient possibilities of connecting additional fittings for special light effects.
Table 32. Intensity of illumination in shop-windows
|
Size of settlement |
Type of street |
Service illuminance in lx | |||||
| | |
Kind of goods | | | | | |
| | |
light, e.g. china, linen | |
medium, e.g. food books | |
dark e.g. cloth fur | |
| | |
Window space | | | | | |
| | |
narrow |
deep |
narrow |
deep |
narrow |
deep |
|
More than 50000 inhabitants |
Business streets, parking places, side-streets |
300 |
500 |
300 |
500 |
500 |
750 |
| |
Boulevards |
500 |
750 |
750 |
1000 |
750 |
1000 |
| |
Central squares, important junctions, main roads, places in front of stations |
750 |
1000 |
2000 |
3000 |
3000 |
5000 |
|
10000 to 50000 inhabitants |
Business streets, parking places, side-streets |
200 |
300 |
400 |
500 |
300 |
500 |
| |
Boulevards |
300 |
500 |
300 |
500 |
500 |
750 |
| |
Central squares, important junctions, main roads, places in front of stations |
300 |
500 |
500 |
750 |
750 |
1000 |
|
Less than 10000 inhabitants |
Business streets, parking places, side-streets |
100 |
150 |
150 |
200 |
200 |
300 |
| |
Boulevards |
150 |
300 |
200 |
300 |
300 |
500 |
The main conditions of the electrical installations are
- that the entire electrical equipment is invisible for the looker-on;- that the freely selectable connection can be easily used by the window-dresser free of accident and at any time.
Besides the adaptation of the shop-window illumination to the space conditions, attention has to be paid to the kind of goods displayed. The articles shown determine the light colour and the type of illumination. Table 34 gives recommendations related to the displayed goods.
Figure 56 shows basic possibilities of designing modern shop-window illuminations.
Table 34. Demands on light colour and type of lighting
|
Goods displayed |
Light colour |
Type of lighting |
Additional light |
|
Glass and ceramics |
fluorescent lamp neutral white de luxe 21 |
direct |
spotlight |
|
Gold, silver, jewels, watches |
fluorescent lamp neutral white de luxe 21 |
direct |
low-voltage spotlight |
|
Books, stationery, pieces of graphic grap, optical articles |
fluorescent lamp neutral white de luxe 21 |
mainly direct |
|
|
Furniture and accessories |
fluorescent lamp neutral white de luxe 21 |
uniform (large) |
|
|
Cloth, garments, leather goods, shoes |
fluorescent lamp neutral white de luxe 21 |
uniform |
spotlight |
|
Cosmetics, hairdresser’s shops, beauty parlours |
fluorescent lamp neutral white de luxe 21 |
uniform | |
|
Flowers |
fluorescent lamp neutral white; filament lamp |
mainly direct |
spotlight |
|
Meat and meat products, baker’s ware |
fluorescent lamp warm white de luxe 31 |
uniform | |
|
Household goods. Technical art. |
fluorescent lamp neutral white 20 |
uniform (large) |
|
|
Cars |
fluorescent lamp neutral white 20 |
mainly indirect or uniform (large) | |
Questions for repetition and knowledge tests
1. What is understood by the term of ‘self-luminous installation’?
2. How are the high-voltage cold-cathode tubes and high-voltage fluorescent tubes fed as regards high voltage?
3. What commonly used switching equipment for advertising installations is known?
Figure 56. Ways of arrangement of fittings
1. front shop-window with little
depth
2. front shop-window with great
depth
3. front shop-window not separated
from the sales room
4. front shop-window with decks
5. corner shop-window or front
shop-window without window head
6. corner shop-window with little
depth
7. corner shop-window with great
depth
8. shop-window that can be looked
over from all sides - passage
shop-window
 |
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