CHAPTER IX. 

 PHOTOGRAPHIC SOLUTIONS 



General Information: 



Stock bottles of all the basic photographic solutions are kept in 

 the Chemical Room, from which they may be issued to investigators. Only 

 the formulas listed in this manual are kept in stock, all others being of 

 a more specialized nature and prepared by the Chemist on order. 



Photo solutions are generally unstable to air and deteriorate on stand- 

 ing if left exposed to the atmosphere. They are also unstable to light. For 

 these reasons, they are always stored and issued in brown-glass bottles, which 

 are initially filled to the top. Orders are drawn from already opened bottles 

 before a fresh, completely-filled bottle is opened. As a guide to the inves- 

 tigator, a table of the keeping properties of photo solutions is included in 

 this manual. 



Preparation of Solutions - General: 



The following list includes all the chemicals necessary for the prep- 

 aration of the formulas in this manual. In every case, photo or technical 

 grade materials are satisfactory, but distilled water should be used in mak- 

 ing all solutions. All formulas are recalculated from those given in the 

 Kodak Reference Handbook. 



List of Photo Chemicals 



Elon (Kodak) or Metol (Ansco) Potassium alum 



or Photol (Merck) Chrome alum 



Sodium sulfite, anhydrous Glacial acetic acid 



Hydroquinone Cone, sulfuric acid 



Kodalk (E.K.Co.) Sodium sulfate 



Sodium thiocyanate Sodium thiosulfate. 

 Sodium carbonate, monohydrate, (rice cryst.. Hypo) 



NapCOo'HpO Potassium ferricyanide 



Potassium Bromide, KBr Potassium dichromate 

 Borax (granular) 

 Boric acid crystals 



Preparation of Developers: 



The six stock developers and their uses are listed in the table below: 

 D-ll...High contrast for films and plates 



-57- 



