The Year Book of Photography and Amateurs Guide For... (Google eBook)

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Photographic News, 1900 - Photography
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Page 465 - The use of the table will be seen from the following illustration : A photographer has a carte to enlarge to four times its size, and the lens he intends employing is one of six inches equivalent focus.
Page 463 - ... the size (linear) of the original will thus require relative exposures of 9 and 81 ie, the latter will require nine times the exposure of the former. It is convenient to have a practical standard for unity. An image of the same size as the original is a familiar case, and serves as such standard. By dividing the figures in the third column by four, we get at the figures in the last column, which represent the exposure required for varying degrees of enlargement or reduction, compared with...
Page 471 - Mix in the order given ; use cold. After exposure, soak the paper in water until limp ; then immerse in the developer. The image should appear slowly, and should develop up strong, clear and brilliant. When the shadows are sufficiently black, pour off the developer and flood the print with the CLEARING SOLUTION. Acetic acid, - - - - - 1 dram.
Page 292 - If a little care be taken to ensure clean dishes and clean fingers, there is no bath more simple or certain. Sulphocyanide of ammonia . . . . . . 30 grs. Gold chloride 2 ,, Water 16 ozs. Tone to exactly the colour desired, judging the prints as they lie in the dish, but it should be borne in mind that the finished image will be slightly bluer and stronger when dry than in the wet state. Wash and fix in Hyposulphite of soda . . . . . . . . 3 ozs. Water..
Page 5 - ... the Requirements of a Perfect Shutter. IT should be simple in construction and not liable to get out of order ; it should be well made...
Page 292 - Alum (potash alum only) . . . . . . 5 ,, Sodium sulphate (not sulphite) . . . . . . 14 Water to . . . . 1 gallon. Dissolve the hypo and alum each in about one quart of hot water, mix, and then add sodium sulphate already dissolved, making up to one gallon with remainder of water. This mixture should then be left for some hours for the precipitate to settle, when the clear solution may be poured off or filtered, and is then ready for use. It will keep indefinitely. No. 2 Stock. Gold chloride ....
Page 491 - ... paper red. Six parts of protosulphate of iron will dissolve in ten parts water, and the whole may be rendered acid by several drops of strong sulphuric acid. To start development, I use a solution composed of six parts of the oxalate solution to one part of the iron, and afterward, if necessary, I add a few drops of a ten per cent' solution of bromide of potassium. It is best to develop slowly. The fixing must be thorough. The rule often given to beginners for determining when a plate is fixed...
Page 465 - The object of this table is to enable any manipulator who is about to enlarge (or reduce) a copy any given number of times to do so without troublesome calculation. It is assumed that the photographer knows exactly what the focus of his lens is, and that he is able to measure accurately from its optical center.
Page 463 - Take the number 2, add 1 to it, and square the sum, 3J = 9. Again, if a copy is to be of eight times the linear dimensions of the original, take the number 8, add 1, and square the sum, 9'= 81. Copies respectively twice and eight times the size (linear) of the original will thus require relative exposures of 9 and 81 ie, the latter will require nine times the exposure of the former. It is convenient to have a practical standard for unity. An image of the same size as the original is a familiar...
Page 292 - ... place the prints, for about one minute, in a solution of common salt, strength unimportant, say one ounce to a pint of water. This removes any last trace of silver, and reddens the print, so that the progress of toning can be more easily judged. After salting, wash for about five minutes before toning. TONING. Any of the ordinary toning baths employed for albumen or gelatine may be used, but no bath gives such rich brilliant tones, either warm or cold, as the sulphocyanide. If a little care...

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