. The principles and practice of roentgenological technique . y be rapidly dried in alcohol by first re-moving the superfluous water, then placing itin concentrated alcohol for five or ten alcohol withdraws the water from theplate. There is usually an increase in densityin this method of fixation. Rapid drying may also be accomplished bythe use of certain salts in concentrated solu-tion. This is only a temporary method. Thussulphite of alumina 100% solution producescomplete dehydration. Among other saltsdoing this are ammonia sulphate (75% solu-tion) sulphate soda (anhydrous 50% so
. The principles and practice of roentgenological technique . y be rapidly dried in alcohol by first re-moving the superfluous water, then placing itin concentrated alcohol for five or ten alcohol withdraws the water from theplate. There is usually an increase in densityin this method of fixation. Rapid drying may also be accomplished bythe use of certain salts in concentrated solu-tion. This is only a temporary method. Thussulphite of alumina 100% solution producescomplete dehydration. Among other saltsdoing this are ammonia sulphate (75% solu-tion) sulphate soda (anhydrous 50% solu-tion) sulphate of zinc (160% solution).According to Lumiere and Seyewetz, carbon-ate of potash in saturated (cold) solution (90grammes in 100 c. c. of water) dries nega-tives rapidly and yet causes no altera-tion of the gelatine, even after prolongedcontact. The negative is plunged into thissaturative solution and washed for a surface water is then removed. It isthen immersed again for four or five min-utes in the saturated aqueous solution of. Fig. 291.—Method of drying dental films. potassium carbonate and pressed between blot-ting paper to remove the greater part of thealkaline solution. Drying is completed bywiping the gelatine coating with a linen plate may later be washed and dried inthe regular way. 212 INTENSIFICATION Intensifying Previous to intensification, the plate mustbe thoroughly fixed and washed if streakingis to be avoided. Better intensification isobtained if the plate has been well dried, andsoaked just previous to the intensification. Solution 1 Bromide Potass 50 g. Mercury bichloride 50 g. Water 1000 ccm. Solution 2 Liq. ammon. caust 100 cm. Water 1000 ccm. These solutions keep and may be used re-peatedly. The plate to be intensified is soaked andthen placed in Solution 1 and constantlyrocked until it becomes gray. The negativeis washed for about fifteen minutes and thenput in solution 2 and rocked. As soon as thenegative has assum
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