LAB REVIEW Terms to understand ... agitate - moving film or paper within the processing chemicals, allowing fresh solution to contact the emulsion. Constant with paper, every minute with film. burning in - adding to an area of the print in order to make that area darker. contrast - the range of gray tones from black to white on either film or paper. Controlled in printing with variable contrast filters. The higher the number the greater the contrast. Because of their density and , filters require varied amounts of exposure. dense - the term used to describe a with too much exposure, overexposed. A dense negative usually requires a low number filter. development time - the time the light sensitive material remains in the chemical generically termed developer. Determined for films by the temperature of the chemical and the ISO of the film. Generally a minimum of one minute and a maximum of three minutes for paper. dodging - decreasing exposure to an area in order to make that area lighter. emulsion - the light-sensitive, silver material, coating on both film and paper The emulsion is the dull side of film, the shiny side of enlarging paper. When printing, work emulsion to emulsion. The shiny side of both should be face up. exposure - the term used to describe the amount of light directed at a light sensitive material, either film or paper exposure time - controlled with the on a , with an interval timer on an . This is one of two exposure controls. fixing time - the time required for light sensitive silver halide crystals to be removed from emulsions permitting finished films and paper to be safely exposed to light. flat- the term used to describe a print with too little contrast f stop - the number on a lens indicating the size of the , the opening in the lens. This is one of two exposure controls. On enlarging lenses: f2 is an example of a large aperture. F 16 is an example of a small aperture. one stop - adjusting the f stop or the time to double or half an exposure. Each f stop is equal to double or half the adjacent f stop. For example, f8 gives twice as much exposure as f 11. opening up - the term used to indicate adjusting the f stop to give more exposure. stopping down - the term used to indicate adjusting the f stop to decrease exposure. thin - the term to used to describe a negative with insufficient exposure, under- exposed. A thin negative usually requires a high number filter.

PRINT FOR THE WHITES. That is, always give enough exposure for large white areas (the high values) to have detail and texture. Only after whites have sufficient density can the proper filter be determined. Filters control contrast and the detail and richness of the low values (shadows).

Chemicals & Functions

Film and paper chemical components differ; their functions are the same.

Developer When an exposed emulsion is placed in the developer those silver halide crystals, which have received sufficient light exposure, are converted to metallic silver. Unexposed silver halide crystals areas remain unchanged. After development, depending on exposure, exposed areas become black and/or various gray values. Unexposed areas will be clear (film) or white (paper). Developers are faster acting at higher temperatures.

Stop Bath Stops development.

Fixer Removes unexposed silver halide crystals. Does not effect black or gray areas of emulsion.

Hypo Clear Shortens wash time. Not used with resin coated papers.

Photo flo For film. Prevents water spots.

Exposure:

Stopping down one stop decreases exposure by half. f2, 2.8, 4, 5.6 8, 11, 16, 22

Opening up one stop doubles exposure. f2, 2.8, 4, 5.6 8, 11, 16, 22

Equivalent exposures are adjustments made to exposure times, or f stops, without altering print density. Example: changing from f8 at 8 seconds to f11 at 16 seconds maintains equal exposure.

Enlarging Lenses for 35mm negatives 50 - 75 mm lens condenser: bottom shelf for 2 1/4 negatives 75 - 105 mm lens condenser: on middle shelf

Readings: Henry Horenstein Photography: Film developing, pgs129 - 150 Printing 161 -207