Science Fair Project Encyclopedia
Darkrooms were widely used in the late 19th and early to late 20th centuries (until about 1980) before color photography became universally popular. Using black and white (panchromatic) film, amateur photographers could get much better results at home for a reasonable price than with factory-developed prints.
Color photography proved to be much harder for the amateur to develop at home due to the increased complexitites of the color process (C-41). This, coupled with the development of Polaroid technology caused a reduction in popularity of home darkrooms.
Darkrooms are often still used on school campuses and photo labs.
The heart of every darkroom is the enlarger, an optical apparatus that projects an image of the negative on a base. Here a sheet of photographic paper is exposed. It is during the inital exposure that the photo can be modified by burning and dodging (i.e. giving parts of the image more light and other parts less by holding objects in the bundle of light, moving them constantly to prevent visible edges in the result).
Other common items found in darkrooms are special timers which will shut off the enlarger and glow enough to be visible without damaging the paper. Most darkrooms also have special print washers used to thoroughly clean the paper. Depending on personal preference, a darkroom may use a paper-safe which is a light-proof box. The use of a paper safe is easier than light-proof bags sometimes used instead.
The paper is then developed, fixed, and dried.
There are different types of paper used in a darkroom. The main types are fiber-based and RC (resin coated). Each has its own advantages and disadvantages. Fiber based paper takes longer to dry because water saturates into the paper while RC paper takes significantly less time. The darkroom operator must be careful with RC paper because water can enter through the edges..
The darkroom does not have to be completely dark when making black and white prints. Red light or low-intensity orange or yellow light, known as safe-lights, make it possible to see when making prints. Black and white film, on the other hand, must be kept in complete darkness until the negatives are fixed.
Since it is much harder to work in a completely dark room for loading the negatives many photographers use a changing bag . A changing bag is a bag with arm holes which is specially designed to be completely light proof. The advantages of using a changing bag is items used in loading a film reel are less likely to fall or be misplaced.
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