The question is not what you are looking at – but how you look andwhether you see.
Henry David Thoreau. A year in Thoreau's Journal 1851.
Human beings have an incredible ability to both look and see. Each of our eyes is equipped with a high quality lens system composed of two well matched lenses. These lenses are intimately coupled with an adjustable iris and a smooth focusing mechanism that allows us to effortlessly change our focus from close-up objects, less than 10
centimetres away, to objects that are effectively at infinity. The light that is collected by the eye is focused onto the retina, a specialised image forming tissue at the back of the eye ball. The retina is packed with millions of specialised light collection cells; arranged in such a clever way that we simultaneously achieve high and low resolution imaging with colour and monochrome imaging.
The muscles that control where we look constantly and involuntarily shift our eye gaze around, so that we can make the most efficient use of the small, very high resolution, patch on our retina called the fovea. Once a light quanta lands on one of the special photoreceptor cells of the retina it begins a biochemical cascade process and sends a tiny electrical signal down one of the millions of individual nerve fibres that are in the optic nerve. These tiny pieces of data travel back into the specialised visual areas in the brain at a rate similar to that of an Ethernet connection. Once the light generated data has got to the brain specialised arrangements of neurons are used to carry out fast
and sophisticated image computation and analysis.
All of the above is refered to as 'normal visual acuity'. Normal it may be, but simple it is not.
Although the biological processes required for normal vision are quite breathtaking this book will take them for granted and I will not spend too much time explaining normal visual literacy. In this book instead, I really focus on how two specialised and ostensibly different professions; art and science, make habitual use of an analytical form of visual literacy that for shorthand I will repeatedly refer to as Intense Seeing.
