. The principles and practice of roentgenological technique . ion by reflected light «jDf theback of the plate. 3. The factorial system. > ^?fr:v^:=V^v^^> Fic. 289.—Seriesdevelopment.(Hodgson.) showhig growth of image withMagnification, 375 diameters. 1. Viewed by transmitted light, the fullydeveloped negative barely transmits the loses some of this density in the fixing bath. 2. Viewed by reflected light, the imageshould be clearly visible on the reverse is usually attained by a 7 minute de-veloper at 65° with a Seed plate. 3. By this method the duration of develop-me
. The principles and practice of roentgenological technique . ion by reflected light «jDf theback of the plate. 3. The factorial system. > ^?fr:v^:=V^v^^> Fic. 289.—Seriesdevelopment.(Hodgson.) showhig growth of image withMagnification, 375 diameters. 1. Viewed by transmitted light, the fullydeveloped negative barely transmits the loses some of this density in the fixing bath. 2. Viewed by reflected light, the imageshould be clearly visible on the reverse is usually attained by a 7 minute de-veloper at 65° with a Seed plate. 3. By this method the duration of develop-ment is determined by noting the time of ap-pearance of the first trace of the image on theplate and multiplying this time by a factor— FIXING AND DRYING 211 the result being the total duration of develop-ment necessary to produce a plate of certaindensity. Each developing agent in normal solu-tion has a certain factorial developing the factor of a particular developer may Thtse Cemparfmenfs15/nches lontj inside T/iese ^ompsrhtmk IStnches toni. -*— 40^ inches ^ Fig. 290.—Tank developing system. be sixteen. If the image appears in fifteenseconds and the factor of the particular de-veloper is sixteen, the plate will be fully de-veloped in four minutes. The factor of metolhydroquinone developer is 14. When the development is complete, the plateis washed in water to remove the superfluousdeveloper, for the alkali prevents the actionof the hypo bath and at the same time dis-colors it. The hypo solution must be kept outof the developing solution. Fixing should be done in yellow but not inwhite light, because fogging will take place.\Mien the unafifected silver has been thoroughlycleaned ofif the plate and the emulsion is prop-erly hardened, the plate is ready for its finalwashing to remove the chemicals. The hypo may be rapidly eliminated by asolution of peroxide of hydrogen. If special water tanks are used, the plate isplaced therein and allowed to wash for aboutan
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectradiogr, bookyear1920
