The advance of photography : its history and modern applications (1911)

Record Details:

Something wrong or inaccurate about this page? Let us Know!

Thanks for helping us continually improve the quality of the Lantern search engine for all of our users! We have millions of scanned pages, so user reports are incredibly helpful for us to identify places where we can improve and update the metadata.

Please describe the issue below, and click "Submit" to send your comments to our team! If you'd prefer, you can also send us an email to mhdl@commarts.wisc.edu with your comments.




We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.

Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.

PSEUDO-PHOTOGRAPHIC EFFECTS 73 passing through glass, mica, or aluminium foil even of extreme thinness, and it is not affected by an electric field. If the resin is dissolved in such an inactive liquid as alcohol, it renders the liquid active. He therefore came to the conclusion that the result could not be due to any radioactive products, but very probably was brought about by vapour given off. Action of Metals. — A large number of experiments of a similar nature have been carried out by S. Saeland,1 in which the action of various metals upon photographic plates were tested. The surface of the metal was first of all cleaned with emery paper and then placed in contact with, or very near to, a photographic plate for a considerable time. A photographic effect was then observed. The effect was greatest with magnesium, next with aluminium, then with zinc. As the metal surface becomes changed by exposure to the action of the air, so it gradually loses its activity in this respect, and it is worth noting that the more active the metal when clean, the sooner does it lose its power. When the surface is again cleaned, the activity is brought back to its maximum value. Not only did the pure metals which were tested behave in this way, but several amalgams, in particular those of zinc, behaved in a similar manner. That this effect is in all probability brought about by chemical action taking place between the metal and the sensitive film is clearly indicated by the following experimental results . If some time elapses between the exposure of the plate and its development, the blackening is much more intense, and a rise in temperature produces a similar result. If the pressure of the air is diminished the effect of the metal becomes less and less, until in a vacuum it has no apparent effect. When dry hydrogen gas is used in the place of air the metal is without effect upon the plate ; 1 Ann. d. Physik., 26, 5, pp. 899-917, 1908.