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PH~MINIATURE

This developer was first introduced (as Paramo!) by the Bayer Co. in II)OI, -N~Cl as the outcome of a new method for the /" preparation of oxyalcohols of the aromatic series, worked out by Eichengr\in in x8gg. The formation of the com-CHsOH pound, as briefly explained by -oH Schweitzer before the American Chemical Society in 1903, is too complex for publication here. Suffice it to say, therefore, that edinol is the hydrochloride salt of meta-amidoortho-oxy-benzy-alcohol, known to the chemist by the formula CJLOHCHsOHNHsHCI. As a developer it stands between the Characteristics slow type, such as pyro, hydroquinone, and the rapid types such as metol, rodinal, amidol, with properties peculiar to itself. It comes in the form of a yellowish crystalline mass. On account of its great solubility it permits the preparation of concentrated stock solutions. In use it is free from fog and staining tendencies and it is non-poisonous, i.e. does not attack the fingers. It is a clear working developer, permits the use of large amounts of potassium bromide without noticeably affecting the contrasts of the image, and is an excellent developer for plates and films, but especially desirable for lantern slides and bromide papers and can be used repeatedly. It is used alone with alkaline carbonates, or in combination with hydroquinone or adurol. At present edinol is not obtainable in this country, but edinol-hydroquinone in powder form, ready for use by simply dissolving in a given quantity of water, is still available. This stock solution is diluted (like Rodinal) according to use. By a molecular combinaOrtol tion of hydroquinone with -QH -QH methyl - ortho - amidophenol /~ ( ) -NHCH1 (x :2), Hauff in 1896 obtained a + H so very useful developer with distinctive properties, which he "/ 'introduced under the trade -QH name Ortol. Commercially, it is the sulphate of monomethyl-ortho-amidophenol with hydroquinone, having E<Unol

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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...

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...

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