How BIG must my sign be?

How LARGE MUST my sign be? What size sign will best convey my message? From how far will people be able to read my sign?

These are questions we often get asked. As a joke, we tend to advise clients that, as a rule of thumb, (a) the bigger the better and (b) the sign should be as large as your budget allows. (Please note this IS a joke and while it is valid for outdoor signs, is not always best for intimate signs, where too big becomes gaudy.)

In truth, if a sign NEEDS to be visible from a specific distance – because it is located on the side of the road or it will only be viewed from moving vehicles or the sign is some distance from the point where it will be read (to name three of many scenario’s), then there are some rough scientific calculations that can be used to calculate the height the text needs to be in order for the text to be visible from a specific distance, as well as from a distance at speed. Please remember, at best, these calculations are rough guide, as they do not take into account ALL factors that affect visibility, especially height above the viewer.

The table below has been adapted from information taken from For more in depth calculations, especially for measuring legible distance while driving, please visit

It is important to remember that the table below refers to LETTER height ONLY. This means that if you have multiple lines of text or multiple words or either of these combined with a logo, the SIZE of THE SIGN will change, with the dependent factor being the DISTANCE at which the TEXT must be legible.

legible sign distance

For assistance for any signs, especially when you need to calculate sign size in order to make the sign legible, please call #SignForce on + 27 (0) 11 440 7524 / 5 or email

How to Illuminate a sign

How should my sign be illuminated – or How do I light up my sign

There are three main directions that a sign can be illuminated, namely FRONT ILLUMINATED, EDGE LIT and REAR ILLUMINATED.

1. Front Illumination – also known as front lighting – refers to the sign being illuminated (lit) from the front, generally either from below or from above, and is commonly used on advertising billboards.

Front illumination is most commonly achieved with bright, ‘spot’ light type lighting, although almost any lighting, including florescent lamps, can be used for front illumination, where the light is being ‘reflected’ off the face of the sign.

Front illumination tends to have the advantage that it can keep costs – both initial investment and running costs – low. This saving does, however, tend to be at the trade-off of clarity and possibly visibility, because one of the largest disadvantages of front illumination is that if the light source is not properly, or well, focused, the sign can become totally illegible at night – just when the lighting is supposed to make the sign visible – as the light reflecting at the incorrect angle can result in the full brightness of the light reflecting off the face of the sign directly into the viewers eyes, similar to the effect of looking into the headlights of oncoming traffic, and effectively blocking the sign’s message.

2. Edge Lighting – also known as side lighting or side illumination or edge illumination – refers to when a sign – generally for a framed glass type sign – is illuminated from one or more side (or edge). Edge illumination is commonly used for safety signs that are illuminated from one edge, as well as for smaller signs that are placed in poorly lit area’s, and ‘slim’ signs that are located in area’s with limited space.

The biggest advantage of edge lighting is that the sign can be extremely thin – from as little as 20 mm deep – so that the illuminated sign can be hung like a work of art or used in the place of a standard piece of artwork, such as a decorative painting.

While there are many advantages to having thin signs, especially when space is at a premium, it is worth remembering that edge lighting can only be used with ‘thin’ light sources, such as T5 florescent tubes or LED lights, so that, for now, (or until the technology improves), the illumination is often not very bright. This does not tend to be an issue if the area where the sign is to hang is poorly or not illuminated, but can be problematic when the area is well illuminated, or there is a lot a ‘other’ light in the vicinity of the sign, as the edge light may not be as bright as the competing light, and thus the most powerful effect of the illumination can be lost.

3. Rear Illumination – also known as internal lighting, back illumination and back lighting – is the most powerful, and most common lighting, used for business signs, building signs and ‘light boxes’. Rear illumination refers to the light ‘passing through’ the face – and illustration – of the sign, thus enhancing the picture, and / or message.

Because of the work involved in the manufacturing and wiring process, rear illumination does tend to be the most costly form of illumination, although the costs are coming down with all the wonderful developments being made in lighting technology.

One of the many advantages of rear illumination is that different types of illumination can be used to create different effects for the viewer. An example of this is when old technology florescent lights (running off magnetic ballasts and starters) are placed behind a picture of running water. Because of the flow of energy in the tubes, the water in the picture also gives the impression that it is moving. While the effect is wonderful, and old technology ballasts are inexpensive when first purchased, it is common for these ballasts to fail. They are also very eco-unfriendly and use a lot of energy because almost 80% of their output is lost to heat.

Modern, energy efficient florescent lights such as the one’s that SignForce use, run off eco-friendly electronic ballasts, and while their cost is constantly decreasing, the initial investment required for this type of lighting is still significantly larger than that required for the older technology, magnetic ballasts. That said, the increased initial investment is WELL WORTH IT, both because of the longer life expectancy of the modern ballasts and tubes, and also because of the lower running costs – both from a power consumption AND a maintenance perspective, as well as the fact that the sign box will not need to have all the ventilation required from the heat generating magnetic ballasts, contributing to a lowing of the manufacturing costs.

It is becoming increasingly common for rear lit signs to be illuminated with energy efficient, eco-friendly LED lights, because of the reduction in running costs, the extended life expectancy of LED lights and the ease of use.

Another advantage of rear illumination is that the picture and / or commercial message is enhanced when the lighting is from the rear, making the message brighter and clearer.

If you are in the market for professional looking, illuminated signs, or simply require advice on how best to illuminate your sign – and get a return on your illuminated sign investment – email or using the subject line: ADVICE PLEASE and we will get back to you as soon as possible.

How long should a sign last?

Long should a sign last? or What is the expected life of a sign?

Often the life expectancy of a sign is linked directly to the cost of the sign.

As as general rule, the more expensive the sign, the longer is will last, but there are a number of factors that need to be considered.

First off all materials are not created equal, and even equal materials will not have the same life expectancy in different locations.

At SignForce we use vinyl that the manufacturer’s say has a life expectancy of five to seven years. While this may be true in Europe and North America, where the climate is cooler tan here in South Africa, we tend to find that five to seven year materials have a life expectancy of around five years. The difference between the better and cheaper options being that the better options tend to shrink evenly, so your circle maintains the shape of a circle, etc.

That is for vinyl. Perspex (or Plexiglas or many other brand names for plastic signs) has an outdoor life expectancy of between seven to ten years, and as long as the sign is not tampered with, this tends to be fairly accurate.

In the harsh African sun good, outdoor digital print and silk screening inks tend to have a life expectancy of between 12 and 36 months, so as a rule the vinyl that is printed on tends to have a life expectancy of no more than three years, as it is figured that the print will fae before the vinyl cracks and peels.

As a buyer of signs what we at SignForce suggest is that you look at the investment over a period of time. A sun that runs and looks bad is BAD for business! That said, if the cost of a print that will last three years is double the cost of a print that lasts 18 months, the latter is actually more expensive, as chances are that in 18 months the latter will cost more and you would thus have been better off looking at the long term cost. Of course, if you only need the print for six months, then a print that lasts 18 months is a better investment.

For great advice on how to have signs that make you look good at a fair price, signs that, as an investment, will generate greater income than their cost, and enhance your image, contact SignForce now. David: Arnold: 0861 SIGNFORCE / 0861 744 63 6723


The Importance of CONTRAST and it’s use in signs

Why is ‘contrast’ important when it comes to signs and visibility?

I was recently putting together a video blog, and in order to make the video more interesting, I began playing with various backgrounds.

WOW, what an eye opener!.

I ALWAYS advise my sign clients that it is the contrast between the message and the background of a sign that makes the message stand out – or get lost, and this video shows how this works. Check out the video at

I am a firm believer that ANY MONEY spent on signs MUST be an INVESTMENT – that is, there MUST be a measurable return on investment. For this to happen the sign MUST have a purpose and MUST be VISIBLE. If either element is missing, the sign will not achieve it’s objective. Contrast is one of the MAJOR contributors to a sign being visible and successful or getting lost in the noise that the background can be.

In case you think that I am making a mountain of a mole hill, check out this video . It is THE SAME sign with different borders, and notice how some borders are so BOLD that you almost forget to look at the sign.

Should you require any signs or advice on signs, or if there is any specific sign related topic you would like me to cover please email SignForce now on or call the office on +27 11 444 3331 to see how we can serve you.

Arnold N. Pollak