Home >> Encyclopedic Dictionary Of Photography >> Acetic Acid to For Washed Emulsion >> Beecheys_P1


ounce, alcohol, bellows, camera, paper, added and silver

Page: 1 2 3

BEECHEY'S PROCESS.—An unwashed collodion emulsion process introduced by Canon Beechey. The following is the simple and efficient modus operandi : Cadmium bromide (anhydrous) 200 grains Alcohol (.8o5). 5 ounces are placed in a bottle and allowed to stand for some hours. The solution thus formed is then carefully decanted, and 4o minims of strong hydrochloric acid added. Then make up Absolute ether (.72o). 9 drachms Pyroxyline zo to 12 grains Add to this ounce of the first mixture, and sensitize by dissolving 40 grains of silver in an ounce of alcohol (.82o) and adding to the collodion. The best method of effecting this is to pound up the silver nitrate in a mortar. Place this in a test tube and add to it first a quarter of an ounce of the alcohol. Boil this until the alcohol becomes slightly brown ; it should then be decanted off and added to the collodion. To the nitrate of silver remaining another quarter of an ounce of the alcohol should then be added, and the operation repeated until the whole of the ounce of alcohol is used, and the silver should then be completely dissolved. Between each addition of the alcohol and silver solution the collodion should be well shaken, and when all is added the emulsion should be smooth and rather thickish. Although at first transparent, the emul sion should after twenty-four hours be very opaque and creamy, and is then ready for coating the glass plates.

The glass plate is first coated or edged with a camel-hair brush round the edges of the plate with a substratum made as follows : White of egg % ounce Water ro ounces Methylated spirit X ounce Carbolic acid lo drops The emulsion, which should be well shaken and filtered, is then poured on and the plates coated in the ordinary manner. When set the plate is placed in a dish of distilled water until all greasiness is removed. It is then immersed in a dish containing beer, to which an ounce of pyrogallic acid has been added, to act as a preservative. The exposure is about twice that necessary for a wet plate. Between exposure and development the plates should not be kept longer than seven or eight days, as after that period they appear to lose brilliancy.

BEER PRESERVATIVE.—See Preservative. BEER PROCESS.—See Albumen Beer Process.

BEESWAX.—The wax of bees, used by them in constructing their cells. This is melted down, purified, and sold as an article of commerce. Beeswax should melt at about 65 deg. C It is partially soluble in alcohol and ether, and totally soluble in chloroform. White wax is the substance bleached by exposure to light and air.

BELLOWS.—That part of the camera which connects the front and back portions. The following instructions for making camera bellows are likely to be useful : First, with regard to the material to be used. Russia leather is the best for a camera bellows, but, of course, the most expensive. Instead of this, however, an india-rubber cloth, stiffened with best quality brown paper, will answer the purpose very well, and possesses several good qualities. It does not become mildewed, nor is it liable to be attacked by insects. It will stand summer heat very well, but in a hotter climate than ours it would be useless, as the excessive heat would soften the rubber, and the folds of the bellows would be sticking together. To make it, glue the india-rubber cloth to the best brown paper attainable, and work it together in such a manner that they are in close contact all over, and no creases or air-bubbles left between. Instead of this a black leatherette paper can be used ; it is obtainable from any dealer in bookbinders' materials. This is mostly used in the cheaper make of cameras sold in the market.

The size of the paper differs, of course, with the dimensions of the camera to which the bellows is to be fitted. We will first give the dimensions of a plain half-plate camera bellows. we say plain, because there are three forms, i.e., plain, conical, and truncated cornered.

It will be as well that a model of the bellows be first planned out on a sheet of paper, then creased and folded so that the operator may become familiar with the necessary manipulations and peculiarities of the folds and manner of folding.

Page: 1 2 3