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MODERN DEVELOPERS

445

A typical formula for development papers is as follows: Water, 32 ounces; Methylol, IS grains; hydroquinone, 6o grains; sodium sulphite (dry), J{ ounce; sodium carbonate {dry), I ounce; potassium bromide (Io per cent solution), 5 to Io drops. Use only sufficient potass. brom. to keep the whites clear. For plates, films, and "soft effect" papers: Water, 32 ounces; Methylol, 10 grains; hydroquinone, 40 grains; sodium sulphite (dry), J4 ounce; sodium carbonate (dry), J4 ounce; potassium bromide, 2 grains. It is recommended that the potass. brom. be first dissolved in an ounce of the water and added to the developer after the other ingredients have completely dissolved. These formulas are, of course, equally serviceable for use with any reliable make of methylated paramidophenol-sulphate (e.g. Gennert's Paramet). Paramidophenol- •Combined with s~phuric acid, p~raSulphate rmdophenol {base) g~.ves us pararmdo-oB phenol-sulphate, a developer introduced by many American and British firms as replacing metol. An average sample contains over 67 per cent paramidophenol, but some brands claim a much -NB,.B,SO higher percentage. It is sold under • its proper name as paramidophenolsulphate, and under many trade names, as Kathol, Fredol, Duital, Mitus (?), Serchol, etc. Strangely conflicting claims are made ccci!f~' for paramidophenol-sulphate as a developer compared with other phenol derivatives. Some makers claim that it is preferable to paramidophenol-hydrochloride, others that it is superior to metol in developing power, while, on the other hand, there are those who say that it is not equal to either in keeping quality, speed of development and capacity for repeated use up to exhaustion. It may be that the conflict arises ~~:!! from a misunderstanding. Paramidophenol-sulpbate used with the alkaline carbonates is undoubtedly "slower" than metol, and, in this respect the chloride salt is perhaps preferable. Formulaa

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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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