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Note that in the use of glycin it is absolutely essential to wash the plates after development before putting them into the fixing bath. Stains will result if this is not done. This is a chemical combination of Hydramine hydroquinone with para-phenylenediamine, made by Lumiere and sold under the trade name hydramine, but not obtainable in this market. It has the formula Ce~ (OH)z + Ce~ (NHt)t. The developing properties of para-phenylenediamine were made known by Andresen in 1888, the combination with hydroquinone being due, apparently, to Hauff. Commercially, para-phenylenediamine is prepared by adding acetic acid to aniline, which is nitrated in the usual way, giving para-nitro-acetanilid which, after reduction by hydrogen, yields paraphenylenediamine. Hydramine comes in white scales or Characteristics powder, readily soluble in warm water, and in conjunction with caustic lithia or formosulphite and sodium sulphite, gives a slow-working out energetk developer, which keeps well and does not stain or attack the skin. A formula given by Lumiere is as Formula follows: Water, 20 ounces; sodium sulphite (dry), 144 grains; caustic lithia, 29,grains; when dissolved, add hydramine, 48 grains. Use a few drops of a saturated solution of potass. bromide per ounce of developer as restrainer when its need is indicated by veiling or tendency to fog. The developer we know as Eikonoge~H Eikonogen, or as it is properly -~ 2 spelled, Ikonogen, belongs to a -QH different family from those we have thus far considered, being a naphthalene derivative. Its HSOa V'-./ developing properties were first made known by Meldola, but its commercial introduction was due to Andresen who, in 1889, gave it the name of Eikonogen-known to the chemist as sodium-amido-beta-naphthol-sulphonic acid, with the formula C,.H.OHNHtHSOa. Caution


Modern Photographic Developers  

A Practical Handbook to the New Developers Telling What They Are and How to Use Them with Reliable Formulae by The Photo Miniature, January...