ABSTRACT
The camera obscura - the original darkened room or chamber from which the modern camera takes it's name - had been known in the Middle East since the end of the first millennium. The difficulties of capturing different wavelengths of light to reproduce colour was way beyond the capabilities of the pioneers who tried simply to capture the presence or absence of white light. A conventional colour photograph is made up of tiny clouds of cyan, magenta and yellow dye that overlap to produce all visible colours. The observation that a solution of certain salts of silver darkens when exposed to light is usually attributed to the German chemist, Johann Heinrich Schultz, working in the early eighteenth century. The very earliest photographic images worked by capturing the effect of shadows left by solid objects on material that was sensitive to light. Digital cameras are even-handed in their response to colour across the visible spectrum.
