What is darkroom technology?

Darkroom is a room that can be completely dark, and it is specially used to deal with light-sensitive materials, including photographic negatives and paper. The establishment of darkroom and its use in photography began in the early1800s. In a darkroom, safety lamps that do not expose photosensitive materials are used as lighting equipment.

In most darkrooms, a magnifying glass is an optical device similar to a slide projector. It projects light onto the substrate through the negative image, and finely controls the focus, intensity and duration of the light to make prints. Photographic paper is exposed to light passing through the negative, thus forming a positive image on the paper.

When printing in black and white, safety lights are usually used to illuminate the work area. Since most black and white papers are only sensitive to blue or blue-green light, red or amber light can be used safely without exposing the paper.

Color printing paper sensitive to all parts of the visible spectrum must remain completely dark until the printed matter is correctly fixed. There is a very dim safety light variant that can be used with some negative color materials, but one of the materials emits very low light, and most printers don't use it at all.

Another use of darkroom is to load film into camera, developing reel or film rack, which requires complete darkness. If there is no darkroom, the photographer can use a change bag, which is a small bag with armholes and is specially designed to be completely opaque for preparing the film before exposure or development.

print

During exposure, the values in the image can be adjusted, most commonly by "homogenizing" (reducing the amount of light in a specific area of the image by selectively blocking light for part or all of the exposure time) and/or "deepening" (exposing only a specific area of the image while blocking the light in the remaining areas and additionally exposing a specific area of the image).

Filters, usually thin colored plastic sheets, can be used to increase or decrease the contrast of an image (the difference between dark and light tones).

A photographic printing method called "split filter printing" is that the photographer uses two independent filters (usually 0 or 00 and 5) to determine two independent exposure times, thus creating a photo. This method allows photographers to get a wide range of colors, highlight details and rich black. After exposure, the photo printing paper (still blank) can be processed.

Photographers usually start printing a roll of film by touching the printed negative as a quick reference to decide which images to enlarge. Some large-format photographers, such as Edward Weston, only make contact photos of large (4x5 ",5x7", 8x 10 "or larger) negatives.

Exposure paper is soaked first? The treatment is carried out in a photographic developer, the development is stopped with a stop bath, and then it is fixed in a photographic fixing agent. The printed matter is then washed to remove processing chemicals and dried. Photographers may take various other extra steps, such as color matching.