The color of light
I took both of these photographs at dawn in Moscow, in Red Square and behind St Basil’s Cathedral, and they both show how attractive early morning light can be – and many of the best travel pictures are taken at the golden hours of sunrise and sunset.
We tend to think of the color of light as white, or even colorless. Yet Isaac Newton himself (well-known as a scientist, but also an alchemist, magician and devout Christian) taught us that when light is white, it is actually made up of a “spectrum” of seven different colors; red, orange, yellow, green, blue, indigo, and violet. Seven colors because he believed light was governed by the same ratios as music (the diatonic scale) and time (the seven days of the week).
Today we’ve reduced those seven colors to three for the receptors in our eyes, each sensitive to a different range of visible light: red, blue, or green. RGB. Mixing those three colors creates the hues that we see.
However, we don’t see all three colors equally well. We are less sensitive to blue, more sensitive to red and very sensitive to green and yellow. Our brains compensate for the blue light at midday and the warm evening and morning light, so we hardly notice the color of light changing throughout the day as the sun crosses the sky – unless we get up at dawn to take a photograph.
In photography and video, modern cameras use the same RGB principle – but when blue midday light is coming through a window into a room filled with warm electric light the result is unnatural and unattractive. Which is where the Gaffer comes in, or the CLT (Chief Lighting Technician).
By measuring the color of light in the Kelvin temperature scale, the Gaffer will balance the light with coloured gels on the windows and on the lights, adding filters to the camera lenses to correct the unmatched light sources.
Even today’s advanced cameras will do much of the work for you, understanding the color of light is still fundamental to film-making and photography – and there is still a place for color temperature meters and light meters to get the exposure right.