The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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Barium Nitrate                                                            Base
crystals. Solubility : I in .48 of cold, and 1 in .35 of hot water ; soluble in spirit, and slightly so in ether. Used in collodion.
Barium Nitrate (Ger., Bariumnitrat; Fr., Azotate de baryum; Ital., Azotato di barite). Ba (N03)2 = 261. Solu-bility: 8 per cent, in cold, 35 per cent, in hot water; insoluble in alcohol. It is poisonous. Used to prepare ferrous nitrate - a developer for the wet-plate process. It is also recommended as an addition to the silver bath to prevent the formation of pin-holes, and has been suggested as an ingredient in magnesium flash-light.
Barium Sulphate (Ger., Bariumsulfat, or Schwerspath; Fr., Sulfate de baryum; Ital., Solfato bi barite). BaS04. Synonym : Heavy spar, Blanc fixe, Mountain snow. Used as a pigment and in the form of an emulsion to prepare baryta paper and imitation opal glass.
Baryta Paper (Ger., Kreide-papier, or Baryt-papier). Paper coated with an emulsion of sulphate of barium, made partly insoluble by chrome alum, and which is used as a support for gelatino-chloride printing-out emulsions and for collotype printing, etc. A formula for its preparation is the following : -
I.
Gelatine, Heinrich's ...        ...        ...      90 grs.
Barium chloride ... ...        ...        ...      30 ..
Distilled water ... ...        ...        ...        5 ozs.
II.
Ammonium sulphate Distilled water
Soak the gelatine in the water till soft, add the barium, and dissolve by heat; then add solution II. in small quantities, shaking between each addition; allow the emulsion to set ; break up into small pieces ; wash thoroughly, and addgrains of chrome alum previously dissolved in a little water.
Base, and Basic. An approximate definition of a base is having properties allied to those of an alkali (q.v.), as far as reacting with acids to form salts is concerned. Basic salts are salts in which the metallic, basic, or electro positive, side
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