Adarkroom is used to processphotographic film, makeprints and carry out other associated tasks. It is a room that can be made completely dark to allow the processing oflight-sensitive photographic materials, including film andphotographic paper. Various equipment is used in the darkroom, including anenlarger, baths containing chemicals, and running water.
Darkrooms have been used since the inception ofphotography in the early 19th century. Darkrooms have many various manifestations, from the elaborate space used byAnsel Adams[1] to a retooled ambulance wagon used byTimothy H. O'Sullivan.[2] From the initial development of the film to the creation of prints, the darkroom process allows complete control over the medium.
Due to the popularity of color photography and complexity ofprocessing color film (seeC-41 process) and printing color photographs and also to the rise, first ofinstant photography technology and laterdigital photography, darkrooms are decreasing in popularity,[when?] though are still commonplace on college campuses, schools and in the studios of many professional photographers.
Other applications of darkrooms include the use innondestructive testing, such asmagnetic particle inspection.
In most darkrooms, anenlarger, an optical apparatus similar to a slide projector, that projects light through the image of anegative onto a base, finely controls the focus, intensity and duration of light, is used for printmaking. A sheet ofphotographic paper is exposed to the light coming through the negative, resulting in a positive version of the image on the paper.
When making black-and-white prints, asafelight is commonly used to illuminate the work area. Since the majority of black-and-white papers are sensitive to only blue, or to blue and green light, a red- or amber-colored light can be safely used without exposing the paper.
Color print paper, being sensitive to all parts of the visible spectrum, must be kept in complete darkness until the prints are properly fixed. A very dim variation of safelight that can be used with certain negative color materials exists, but the light emitted by one is so low that most printers do not use one at all.[citation needed]
Another use for a darkroom is to load film in and out of cameras, development spools, or film holders, which requires complete darkness. Lacking a darkroom, a photographer can make use of achanging bag, which is a small bag with sleeved arm holes specially designed to be completely light proof and used to prepare film prior to exposure or developing.
During exposure, values in the image can be adjusted, most often by "dodging" (reducing the amount of light to a specific area of an image by selectively blocking light to it for part or all of the exposure time) and/or "burning" (giving additional exposure to specific area of an image by exposing only it while blocking light to the rest). Filters, usually thin pieces of colored plastic, can be used to increase or decrease an image's contrast (the difference between dark tones and light tones). One method of photographic printing, called "split filter printing," is where the photographer determines two separate exposure times using two separate filters (typically a 0 or 00, and a 5) to create a single print.[3] This method allows the photographer to achieve a broad tonal range, with detailed highlights and rich blacks. After exposure, the photographic printing paper (which still appears blank) is ready to be processed.[4]
Photographers generally begin printing a roll of film by making acontact print of their negatives to use as a quick reference to decide which images to enlarge. Somelarge format photographers, such asEdward Weston, make only contact prints of their large (4x5", 5x7", 8x10" or larger) negatives.
The paper that has been exposed is processed, first by immersion in aphotographic developer, halting development with astop bath, and fixing in aphotographic fixer. The print is thenwashed to remove the processing chemicals and dried. There area variety of other, additional steps a photographer may take, such as toning.
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