50 The Microscope 



sulfite and sodium carbonate. Neither the composition nor the tempera- 

 ture of paper developers is so critical as that of film developers. Most 

 people keep one stock paper developer and use it at room temperature. 



Development time varies with papers but is usually from 1% to 3 min. 

 Underdevelopment is a common fault. It is usual to stop development in 

 a bath of 2 per cent acetic acid— hardening is not necessary— and fix in the 

 same fluid used for films. Fixation and washing require a longer time 

 than do films, since the reagents must be removed from the paper base 

 as well as from the gelatin film. 



Glossy prints are given an extra high gloss, and dried relatively flat, by 

 being rolled face down onto a highly polished, chrome-plated sheet. 

 This is usually in the form of a heated drum protected by a canvas belt, 

 or a flat sheet with a canvas cover. 



Papers are universally processed in trays, which should be considerably 

 larger than the sheets used. The tray is filled out two-thirds full and the 

 paper, face up, is slid under the surface. The tray is continuously rocked 

 during development, but prints are usually left in a large tray of fixer 

 with only an occasional stir. The utmost care must be taken not to get 

 fixer into the developing tray since even the slightest trace of contamina- 

 tion is ruinous to the image. If prints are handled with tweezers, a sepa- 

 rate pair should be kept for each bath. If hands are used, the left hand 

 alone should enter developer, the right hand should enter fixer. 



Prints can be properly washed only in a device that combines continu- 

 ously agitated running water with periodic emptyings of the container. 

 Many such devices are on the market. An hour is none too long to remove 

 thiosulfate and silver from the paper base. 



Figs. 59 and 60. Processing paper. Fig. 59. The undeveloped paper is slid sideways 

 under the surface of the developer. Fig. 60. The developed paper is slid sideways 

 into fixer. Notice that the left hand is used for developer and the right hand for 

 fixer. This prevents any possibility of contamination. 



