The Dictionary Of Photography

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

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Iron, Ammonio-Sulphate of                       Iron, Sulphate of
and evaporating greenish-white crystals, which are partially re-duced by light to a ferrous state. Ninety parts are soluble in ioo parts of cold water, and 126 parts in 100 of boiling water. Used in platinotype and blue-printing processes.
Iron, Ammonio-Sulphate of (Ger., Schwefelsaures Eisen-oxydulammoft; Fr., Sulfate ferreux ammoniacal; Ital., Solfato di protossido di ferro e d'ammoniaca). Fe(NH4)22S046H20 = 392. A double salt of iron and ammonium, proposed as a sub-stitute for ferrous sulphate; but its action is much feebler, though the salt and its solution are more stable. One ounce of ferrous sulphate is equal to i£ ozs of the double salt. Solubility: about 1 in 6 of cold water; insoluble in alcohol. Was frequently used for developing wet collodion plates.
Iron, Oxalate (Ferric) (Ger., Oxals&ures Eisenoxyd, Fer-ridoxalat; Fr., Oxalate ferrique; Ital., Ossalato di perossido di ferrd). Fe2(C204)3. Obtained by precipitation, and nearly insoluble in water. Soluble in oxalic acid and alkaline oxalates.
Iron, Oxalate of (Perrons) (Ger., Eisenoxalat; Fr., Oxalate ferreux; Ital., Ossalato fertico). FeC204. Prepared by decom-position of sulphate of iron with oxalic acid. It is but rarely used dry, being generally prepared as wanted in solution by double decomposition by adding solution of sulphate of iron to solution of oxalate of potash. (See Developer.) It is sparingly soluble in water, more soluble in any solution of alkaline oxalate. It is the developing agent of the ferrous-oxalate developer.
Iron, Per chloride of (Ger., Ferrichlorid, Eisenchlorid; Fr., Perchlorure de fer} Chlorure ferrique; Ital., Cloruro ferrico)^ Fe2Cl6. Synonym : Ferric Chloride. Prepared by passing chlorine over hot iron filings, when the ferric chloride distils over. It can also be made by dissolving iron wire in hydro-chloric acid, adding nitric acid, and heating till the ferrous chloride first formed is converted into ferric. It occurs in yellowish-red opaque masses, which are very deliquescent. Solubility: 160 per cent in cold water; soluble also in alcohol and ether. It is used for the reduction of negatives, for cyano-type paper, also for etching copper and zinc.
Iron, Sulphate of (Ger., Eisenvitriol} Schwefelsdures Eisenoxydul; Fr., Sulfate ferreux; Ital., Solfato di ferro).,