Commemorative Exercises at the Fiftieth Anniversary of the Franklin Institute of the State of Pennsylvania for the Promotion of the Mechanic Arts. Held on Friday Evening, February 6, 1874, at the Musical Fund Hall (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 Excerpt: ...the method of producing those extraordinary heliographic pictures, known as the Daguerrotype. Who that is of sufficient age does not remember the amazement and delight with which he first inspected those charming pictures of trees and buildings, landscapes and grazing herds, with all their minutest details sketched by the sun, on the silver plate with his own actinic pencil; and then a little later their intense enjoyment through the sentiment involved, of those speaking portraits of loving friends, first produced by our philosophic investigator Prof. Draper? In 1839 Mr. Fox Talbot first successfully produced what he called " photogenic" drawings, upon paper first charged with iodide of silver, then dipped in nitrate of silver and subsequently in iodide of potassium, and after exposure to the object developed to view, by washing in a mixture of aceto-nitrate and gallic acid, and finally fixed by means of hyposulphite of sodium. From this has sprung the exquisite art of modern photogrcqjhy, which in its many sided applications has become a familiar and almost necessary member of every household. Quickly following the Talbotype, we have bad devised in rapid succession an almost endless variety of modifications of the paper photograph, and we now witness as but of yesterday that triumph of patient skill in this same progress, the Woodburytype, which first calls upon the sun to paint his faithful picture upon the sensitized film, then transfers it with un-failing accuracy to a metallic plate, from which it may he printed on paper by means of appropriate ink, as in lithographic or copperplate work. To this may be added the still more recent, and perhaps more perfect invention just coming into use, which, under the name of the Heliotype accomplishes the...