TAOP: Part 4 – Light: The Colour of Light – Project Introduction
March 22, 2012
This section begins by talking about light wavelengths and the visible light spectrum.
Sunlight is our standard not only for brightness, but for colour. In the middle of the day it seems colourless – we usually call it ‘white’.
The eye is more sensitive to some colours than others and brightness will appear highest around yellow.
The text states daylight normally becomes coloured in two directions and asks what they are. I’d think it tends to go from blue to orange (thinking about the goldish-colour of evening sun).
The text actually goes as far as red, by the time the sun reaches the horizon. This is due to shorter wavelengths being scattered by the atmosphere leaving only longer wavelengths visible.
The blue is scattered, meaning in shade the light comes from the scattered blue – so daylight will go from red, through orange, straw-coloured, white to blue. This is important as there are times in photography where coloured daylight is not wanted, and this is even more important when considering tungsten light.
The colours above represent the ‘colour temperature scale’ for reasons more to do with underlying scientific principals than with photography. Colours of the sun can be given a figure in degrees of temperature (e.g. think of iron being heated – going from red, to white-hot, to blue). The scale is measured in Kelvin.