The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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Diogen Developer                                                 Distortion
Diffused light in the camera is generally taken to mean any actinic light other than that passing directly on the plate from the lens.
Diogen Developer. See Development and Developers.
Dish. One of the most necessary articles of an amateur's outfit. Dishes are made of various materials: glass, earthen-ware, vulcanite, metal, and wood being the most useful. Dishes should be kept scrupulously clean by occasionally scrubbing with a stiff brush and some strong acid. One dish should, where practicable, be kept specially for each operation, and used for that only. The tourist can often extemporise a dish by folding up the margins of a sheet of writing paper, and fastening by means of four pins.
Dispersion. An optical term used to denote the separation of a ray of heterogeneous light by refraction into its component rays of different refrangibility. Different transparent media have different dispersing powers, or different powers of widening the angle between the red and violet rays, and it is owing to this difference of dispersive power in different kinds of glass that chromatic aberration can be eliminated.
Dissolving Views. See Magic-Lantern.
Distance. The objects in a landscape farthest from the eye> forming a background to the scene ; and, in an artistic sense, the representation of objects so as to give an idea of remoteness. (See Aerial Perspective.)
Distilled Water. HaO=i8. Pure water obtained by vapori-sation in a still or retort, and subsequent condensation of the vapour. It should be used in many operations of photography, especially in the manufacture of emulsions and ferrous oxalate development.
Distortion. Images may suffer from no less than three kinds of distortion, (a) distortion of perspective, (b) distortion of parallel lines, and (c) distortion of marginal lines or the aberration of thickness of the lens.
(a) Distortion of perspective. This is frequently noticeable in ordinary work, particularly in architectual studies where lenses of
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