TECHNICAL TERMS  -  D
DX-CODING
  • A system of coded markings on the film cassette that automatically programmes the correct film speed into the camera. 
​DAYLIGHT FILM
  • Film designed to use in daylight or with a flash.
​DEPTH OF FIELD
  • The area of acceptably sharp focus extending both in front of and behind the point of focus. Depth of field varies depending upon the aperture selected, the focal length of the lens and the focal distance.
​DEVELOPMENT
  • Chemical process of converting exposed film emulsion to a visible image.
​DIFFUSED LIGHT
  • Even, shadowless light found in overcast weather.
​DIN
  • Deutsche Industrie Norm.  Same as ASA and ISO.  German standards organisation for film speed rating
​DODGING
  • A printing term used to describe using a small device to block those parts of an image that would benefit from less exposure under the enlarger. 
  • These parts have to be shaded from the enlarger light while the rest of the paper receives normal exposure.