The Dictionary Of Photography

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

	Deviation	Dextrine
	of intensification. (See Intensification.) Dr. Haschak recom-mends that, in place of the rodinal as recommended above, the following should be used : -
	Water ...        ...        ...        ...        ...        ... 35 ozs. Metol .................. | oz. Sulphite of soda (anhydrous)           ... ... 5 ozs.
	Colouring the Developer with a Non-actinic Dye. This is sometimes done, as it allows the dish to be taken out into the light. (For a suitable colour-mixture see Aurantia.) Simultaneous Development and Fixing. This is perhaps rather an eccentricity in photography than a method of practical value, as, by combining the above processes, there is a loss of much of that complete control which is so desirable. A de-veloper which will simultaneously fix the plate can be prepared as follows: -
	Pyrocatechin Caustic soda . Sulphite of soda Hyposulphite of soda ... Water ...	40 grs 5 ft 1 oz. 70 grs 10 oz.
	Long Continued, or Stand Development. This is treated of in a special article. (See Stand Development.) Development by Time. Mr. Alfred Watkins has much insisted on the desirability of a system of development by time, and in connection with this system he has devised a special clock which he calls an " Eikronometer." This system of develop-ment is treated of under the heading, Time, Development by Deviation. An optical term to denote the alteration of the course of a ray of light when it is refracted or reflected. Dextrine (Ger., Starkegmnmi; Fr., Dextrine; Ital., Destrina). Synonym : British Gum. Is made by heating starch until it loses its insolubility in cold water, or by heating it in the presence of a dilute acid. It is usually a pale buff powder, and is used as a substitute for gum. Tested with litmus paper it should not give an acid reaction. (See Mountants.) 205