So what do you need to consider when selecting a light source for your sign? The objective of illumination is to highlight a sign against the general background clutter, encouraging the eye to focus naturally to the signage. Before starting to design the sign you need to decide how you are going to get electrical power to the area and what restrictions there may be. You may discuss with your customer general ascetics, brightness levels and what staff are available to maintain the sign. You will then be able to supply a quotation that gives them information on running costs and longevity of the light.
Lighting is normally measured in lux (a unit of measurement) and refers to the brightness to a set area in relation to the beam spread. For example, if the spread of 2000 lux illuminates a square metre set at two metres from the source then the measured lux level could be 1000 lux, if you take the same measurement over four metres it is likely to be 250 lux.
The choice of light sources seems endless, including fluorescent tubes, Dichroic lamps, LED strips and individual extra bright LEDs, as well as new light sources continually coming on to the market. In this article I consider illumination in the context of a sign rather than a light box.
For years fluorescent tubes have been used as an economical way of illuminating signs from above. The tubes are normally positioned just above the sign and give out a stark light that appears lifeless and may have a yellow tinge. Fluorescent tubes give a whitewash effect that is functional but not eye catching or attractive.
A more natural white light can be achieved by using SAD (seasonal affective disorder) lighting, which gives a very white light. Remember, when specifying a specialist tube your customer must be able to get hold of replacements easily.
LED strips or individual extra bright LEDs are the current hot topic to use for lighting but be careful, you must really think about what you want to achieve with this type of lighting. It has an attractive visual appeal and does have a great strength of light but it is does not transfer the light to the surrounding area. LEDs are excellent for short range lighting e.g. panel edging or for creating special effects and creating a shine.
The subtlety of lighting signs is a careful balance of illuminating signage but without spilling light into unwanted areas.
Dichroic are directional and you have much more control of light and are excellent for illuminating all types of signs. They enable you to create feature lighting using standard white lamps or transform the appearance of a sign by using a mixture of colour lamps. For brightness and economy dichroics are still excellent value especially when you use lamps that can have up to 10,000hrs of lamp life.
A sign suspended in the window with dichroic lamps positioned above suspended cables allows the lighting to be positioned in the correct place to give the best possible results. Consider what type of light spread do you want to achieve? Is the light to just illuminate 500mm high x 600 mm wide panel or does it need to illuminate a sign that is 2000 mm in height?
The above is an extract. To find out more, book a place on one of Fairfield Displays and Lightings’ free seminars to help signmakers and large format graphics companies use lighting with confidence. The next seminars are on 21 January in Fleet, Hampshire and 28 January 2009 in Shrewsbury, Shropshire. Full details can be found at www.fairfielddisplays.co.uk or telephone 08451 665201.