Hobbies And Interests
Cellulose and Chemicals
Photographic film is a cellulose or plastic strip, wrapped onto a spool and impregnated with light-sensitive chemicals called silver halide salts. Silver halide particles are altered when exposed to light, as the lens of a camera focuses an image on this surface for a brief time. The changes on the light-exposed silver halide cause the particles to solidify in developing chemicals, and during development, the non-light-affected silver halide washes away as the light-struck areas become darker.
Positive and Negative
Making the final photograph is a two-step development process. The first step is development of the negative, where the color or light intensity on the film itself is the opposite of the actual photographic subject -- light where it is dark, or with complementary colors. That is why the processed film images are called negatives. The second step is production of the print, or the finished photograph. As focused light is shone through your negatives onto a sheet of chemically impregnated photographic paper, the paper̵7;s chemicals undergo another color reversal process, which results in a positive, where light and dark, or colors, are then represented as they are on the actual subject. As in mathematics, two negatives make a positive.
Complementarity
Black and white photographic negatives only represent intensity of light, not separate colors, so the negative is also black and white. Black on the negative will turn out white on the positive; white will turn out black. This reversal of light from subject to film is called complementarity. Likewise, color negatives will appear on the film as the opposite of what is seen. Color complementarity also means opposites. The three basic colors are red, blue and yellow. Red is complementary to green, a combination of blue and yellow; blue is complementary to orange, a combination of yellow and red; yellow is complementary to purple, a combination of blue and red; and there is a theoretically infinite number of degrees between each.
Handling and Storage
Handling and storing negatives requires some care. Try never to touch your negatives on the flat planes; hold them between your fingers by the edges. Fingerprints can attract dust, and anything that obstructs light through the film will alter the final print image. Negatives can fade if exposed to heat, moisture or chemicals. Keep them in plastic film containers, and store the containers in a cool, dry place.