THE origins of modern photography go back to the ancient concept of the camera obscura, well known to Arabian scholars in pre Renaissance times. In its simplest form, the device consisted of a dark room into which light was allowed to pass through a small hole, allowing an image of the scene outside to be projected on the opposite wall. The idea was miniaturised by 16th century artists as an aid to fathoming the mysteries of perspective, and the invention of lenses not long afterwards allowed the image to be sharply focused.
It was not until the 19th century, however, that techniques to preserve such images were perfected. In the late 1830s, the Frenchman Louis Daguerre, with his daguerreotypes, developed a way of fixing the image on to metal, and in the following decade photography as we know it today became a reality.
Photographers become experts at using sunlight to achieve their desired effect. They think, for example, in terms of "hard" and "soft" illumination, irrespective of its brightness. "Hard" light is that available when the sun is unobscured; it casts strong, sharp shadows, giving images vitality and "punch". The light is soft", on the other hand, when the sunlight is diffused by cloud, or perhaps by some artificial means indoors: the resulting absence of harsh shadows makes a picture soothing to look at, and means every detail of the subject can be captured.
As the sun travels across the sky between dawn and dusk, the quality of its reflected light changes by the hour. There is a period just before the dawn, a kind of twilight, when the diffuse light from the eastern sky delivers very weak shadows. As the first rays of sunlight break across the horizon, however, long thin shadows rake across the ground, revealing form and texture in the landscape, and making this time of day ideal, say, for travel photographs.
But as the sun climbs higher in the sky, and shadows shrink, the colours lose their vivid individuality, and there is a pervasive harshness, almost whiteness, about every scene: human subjects have a pale and pasty look, and hidden by hard shadows, their eyes appear in photographs as black and lifeless voids.
By mid afternoon, however, the descending sun and lengthening shadows once again impart a three dimensional feel to any landscape. And when the sun has disappeared below the western horizon, photographers often seek out lake land scenery and seascapes, to capture the blue and pink and purple shades of twilight reflected in the water.