Darkroom – A room without lights that is used to develop and process film and prints.
Developer – The chemical that removes the first layer of emulsion from film or photographic paper and allows the image to be seen.
Developing Tank – A special light-tight tank used to develop film. It has a special pouring area that allows the developer to be added and removed without exposing the film to light.
Diffraction – When light becomes modulated when passing through the camera lens and redistributes the light unevenly. Edges will have a fuzzy appearances and shadows will have visible bands of light.
Dodging – Blocking light from an area of the photographic print to lessen the amount of exposure and lighten that particular spot.
Double Exposure – Exposing film twice allowing for two similar or different images to overlap on a single negative.