Photography

When you think of how many centuries passed in which images were created exclusively by hand, you can appreciate how revolutionary the photograph was. A crude type of camera called a camera obscura, which was invented in the beginning of the fourteenth century, captured and projected light on a surface. However, it wasn t until 1826 that the first true photograph was taken. Early photographers needed special equipment and a broad knowledge of chemistry to produce photographs (see Figure 1.7). As a result of the scientific and technical discoveries of the 19th and 20th centuries, cameras became more efficient and easier to operate . Now, millions of still photographs are taken and processed every day.

Figure 1.7: Lady Clemintina Hawarden, photograph of a model, 1860

A camera is very much like the human eye. Light rays enter a camera and are focused on a surface into an image. Film rests on the surface and is exposed, causing a chemical reaction. The exposed film is then bathed in certain chemicals in a process called developing. If the film is a negative, light passes through it onto a piece of photosensitive paper. The paper is developed, stopped , and fixed, producing a positive photographic image.

Several tools, filters, and operations are specially designed to make the photographer feel right at home in the digital Photoshop environment. In fact, Photoshop is a virtual darkroom that includes tools to dodge, burn, saturate, enlarge, crop, mask, and, of course, correct and adjust color. New digital printers are available that focus laser light on photosensitive materials to produce continuous-tone color prints and transparencies .

As a result of the popularity of computer programs such as Adobe Photoshop, digital cameras have become a recent addition to photo technology. Digital cameras create pictures that can be transferred to a computer or television set. The digital camera s lens focuses light on a light-sensitive mechanism, either a charge- coupled device (CCD), or to the newer complementary metal-oxide semiconductor (CMOS) chip. The electronic pictures can then be stored on disks or opened in a computer graphics program. With additional equipment, electronic images can also be sent over telephone lines or printed on paper.