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The Poetics of Stage Lighting: A Zen approach to theatre technology COLOUR- The inside facts about Colour page 2

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Take my tip.....

If ever you go to see a psychotherapist, on no account tell him that your favourite colour is Orange-Red. To them this denotes eccentricity, hyperactivity, aggressiveness, competitiveness and shows too much in the way of domination and sexuality.

If on the other hand you tell him that you like blue, he will pass you out with flying colours (to coin a phrase) as you will be sensitive, perceptive and unifying, expressing tranquility love and affection.

What is your favourite colour ? Think carefully! you may be telling me more than you think you are!

Most of our colour names come from Newton who split up white light into the colours of the spectrum with a prism. He decided to have seven major colour names to be in harmony with the seven then known planets, the seven notes of the scale and so on. Other civilizations have names for fewer or greater numbers of distinct colours. Some make no distinction between blue and green, but split light green and dark green into two different colour names.

Can we agree on what colour is? I doubt it! All we can say for certain is that we have agreed among ourselves that on balance, daffodil flowers are what we shall call ‘yellow’ and when there are no clouds on a fine day, we shall agree to call the sky ‘blue’, and when we mix up paints made of the said yellow and blue we are left with what we call ‘green’ , which is jolly handy because that’s what the colour of the stuff that grows on the park floor is.. more or less..

This all sounds jolly straightforward doesn’t it ? But come to think of it what I call green may not be green to you but blue. Take a bit if No 138 Lee filter Is it green or is it yellow? Hold up a bit of no 121 next to it and compare them and there's no doubt. Its yellow. Now hold up a bit of 101. Suddenly its not so yellow after all. Its obviously been a nice cold green all along!

Think about the following questions. I’ll come back to them later:

What colour is snow?
What colour is moon light?
What colour is the sky?


It is perceived in different ways according to local and psychological conditions. Colours which look identical under certain light conditions can look markedly different under another set of lights. Newton called this Metamerism.
If you want to test this, prepare ten pieces of different coloured paper - white, grey, pink, light brown, pale green, lilac, sky blue, bright red, bright green, and yellow - and label them on the back. On a clear night, select a dark spot outside which is illuminated only by the light of the Moon and (after shuffling the paper and without looking at their labels!) attempt to identify each colour. The red one may turn out to be the only one which can be identified with certainty, and only then if the moonlight is bright enough. Under low pressure sodium street lighting (SOX) you will be able to perform another experiment, this time illustrating a psychological aspect of human colour perception. When the Moon is high and near full, stand close to an orange street-lamp and face the Moon. Observe the colour of your shadow being cast on the ground by the lamp. It will seem indisputably blue, though in reality your shadow is being faintly illuminated with moonlight which is white, not blue.

One of the most important modifiers of our perceptions is the type of light under which it is viewed

All light sources, natural and artificial have three sets of characteristics.

This indicates what the lamp looks like, i.e. Is it warm or cool, is it a rosy cosy glow or a nasty amber street light colour?

This indicates how colours of other object look under the influence of this light, i.e., a red car under a low pressure sodium street light looks black. Even a lamp which ostensibly produces white will render colours in a characteristic way. The colour rendering index ( The Ra. figure) is a comparison of the rendering of colours compared to a reference source. A Ra of 100 is theoretically perfect.
Low pressure sodium gives a largely monochromatic output and cannot render colour, other than its own at all. A colour rendering index of 90-100 Ra is required for accurate colour matching, i.e. in a printers or a paint factory. 80-90 Ra is generally satisfactory in a commercial or retail outlet other than a clothes shop.
The important thing is to provide the colour temperature which makes the goods and the customer who might buy them look and feel good. In a good hairdressing salon, you need several different light sources. For tinting and dying a good colour matching light source will definitely be required to prevent very expensive and distressing mistakes. It is a hairdressers nightmare that a customer looks good in the chair but looks terrible outdoors or in the club, so to check the colour under all likely use conditions, you will also need a warm white fluorescent and a halogen spotlight. It is worth noting through that skin tones don’t look their best at anything over about 80 Ra. and can be very unhappy looking at themselves in a mirror so a real lighting design is required to produce good compromise with warm skin tones without compromising the colour rendering.

In a clothes shop, it is normal to increase the red content a little. In Butcher’s shops a considerable red content is needed, and special lamps are available. Greengrocers need the opposite, the blues enhanced.

Where live plants, tropical fish and pets are grown or sold, a complex changing cycle of artificial daylight, with a controlled degree of added ultra violet light (UVB) is required , used with care and caution

This is an index of the degree of absolute colour rendering ability. It is measured in degrees Kelvin i.e. 3500? K.

A bright blue sky has a collimated colour temperature of 10,000? K, where a warm white fluorescent tube is nearer to 3500? K, and a filament lamp may be 2700? K or so.

colout temperature


Lamps with a CCT (Collimated Colour Temperature) of <3500K are usually described as having a "Warm" appearance, Those with a CCT of >3500 - <5000K considered to have a "Cool" appearance, Those having a CCT of >5000K are said to have a "Cold" appearance.


High pressure sodium lamps - 2000K to 2200K
Tungsten filament light bulb - 2700K
Tungsten halogen lamps - c.3000K
Fluorescent lamps - various 2700K to 6500K

Metal halide lamps - various 3000K - 5600K
Noon sun - 5500K
Blue sky - 10000K

Colour temperature control is fundamental to the well being and happiness of the human body. A day in the natural world comprises a constantly changing balance, with a low colour temperature making way to a very high CT at the height of the day, tending to the blues in the afternoon as the sun gets lower in the sky and refracts in a different way. Experiments have shown that both the hormone balance and the natural rhythm of the body can be seriously upset when the expected colour temperatures are not present.

I ASKED EARLIER ………. What colour is Snow?

White did I hear? Certainly not! Next time you can, go and look at some. And this time really look properly. I think it is actually pale lemon with deep violet shadows. You might disagree. You may say there are chocolate browns and pale blues.

Snow is composed of lots of crystals of ice. Ice is colourless so what we actually see is light being both reflected and refracted.

I ALSO ASKED ……….what colour is moonlight?

This is the most difficult of all questions to answer as the answer seems to be that it is genuinely colourless . If really pressed you might say that it is “ monochrome” or “silvery”

When our eyes are dazzled by the full Moon riding high in the sky, it is difficult to acknowledge the fact that the Moon is really a very dark object. The actual intensity of moonlight is only a quarter that of a burning candle placed a metre away - 0.25 lux ( starlight can be as low as 0.00005 lux) . This is so low that the colour-sensitive "cones" in the eye cannot kick in, and the “rods” have to cope on their own. Rods are particularly sensitive in the shorter wavelengths. This makes the characteristic “cold” colours appear brighter than they might otherwise. Also as the moon is effectively a point source at that distance, there is little diffusion. Therefore the shadows are very black which improves the contrast.

There is a complete article on moonlight lighting for the stage here

And exactly what colour is the sky?

Ah, Trick question. The sky of course is colourless because it consists only of not very much and most of that invisible. But it looks blue sometimes due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air. However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue. As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white.

Bear this in mind when lighting a Cyclorama. If you use cyc floods with assymetric reflectors, the light intensity and colour will be more even, but 'normal' reflectors will create an intensity and colour gradient, with the darker colours near the top fading off as it gets lower. Add to that an uplighting batten with Asymetric reflectors in a lighter colour, which, balanced with care, will create a horizon effect.

What about the setting sun?

As the sun begins to set, the light must travel farther through the atmosphere before it gets to you. More of the light is reflected and scattered. As less reaches you directly, the sun appears less bright. The color of the sun itself appears to change, first to orange and then to red. This is because even more of the short wavelength blues and greens are now scattered. Only the longer wavelengths are left in the direct beam that reaches your eyes. The sky around the setting sun may take on many colors. The most spectacular shows occur when the air contains many small particles of dust or water. These particles reflect light in all directions. Then, as some of the light heads towards you, different amounts of the shorter wavelength colors are scattered out. You see the longer wavelengths, and the sky appears red, pink or orange.

My favourite sunset method it to use several profile spots lighting the cyc with horizonal breakup goboes, focussed very brown and fitted with various split dual colours. Several cues will be required to make a convincing effect. For tropical sunsets, be heavier on the browns and oranges, with - paradoxically - just a touch of green. Its a psychological / cultural thing. Sunsets are actually highly unlikely to be green!

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