Preparation of Hardener F-5A: (8 liter batch) 



This is mixed in the same jug with the same stirrer as was used on 

 the developers. Ingredients are added in the order listed below: 



1. Distilled water (50°C) 4800 cc. 



2. Sodium sulfite, anhydrous 600 g. 



3. Acetic acid, glacial 513 cc. 



4. Boric acid crystals 300 g. 



5. Potassium alum 600 g. 



6. Cold water to make 8 1. 



Preparation of 30% Hypo: 



If making a 12 liter batch use 3600g of the Hypo(Sodium Thiosulf ate ) , if 

 making an 18 liter batch use 5400g of the Hypo. By dissolving the Hypo in sep- 

 arate batches the crystals may be made to go into solution more easily and more 

 quickly. Therefore, if making a 12 liter batch use two portions of distilled 

 water of 6 liters each int.o which are dissolved 1816g (41bs.) and 1784g (3.91bs.) 

 respectively. If making an 18 liter batch it is best to dissolve the Hypo in 

 three separate 6 liter batches with 1816g (41bs.) of the Hypo in two of the three 

 batches and 1784g (3.91bs.) in the third batch. It is easiest and more conve- 

 nient to pour the one pound boxes of the Hypo directly into the stirring jug as- 

 suming them to be fairly accurate pounds. Any colloidal cloudiness will clear up 

 in a day or two while in the carboy. However, the Hypo can be used even though 

 it is cloudy. The cloudiness does not affect its effectiveness. Each 6 liter 

 portion is poured into the carboy and then the carboy is placed under the pres- 

 sure system beside the hardener. 



Preparation of Stop and Hardening Baths: 



1. Stop Bath SB-1: (1.3% Acetic acid) 



For papers and plates. 13 cc. of glacial acetic 

 acid in 1 liter of water. 



2. Hardening Bath SB- 3: (3% Chrome alum) 



For use at summer room temperatures with films and 

 plates. 30 g. of chrome alum dissolved in 1 liter 

 of water. 



3. Stop Bath SB-5: (Non-swelling acid rinse for Photo 



finishing) 



Water. 500 cc. 



Acetic acid, glacial 9 cc. 



Sodium sulfate crystals .. 105 g. 

 Water to make 1.0 1 



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