21 de Março
ABSTRACTS OF THE PAPERS,
PRINTED IN THE PHILOSOPHICAL TRANSACTIONS
ROYAL SOCIETY OF LONDON
1837 to 1843
Proceedings of the royal society
IV. “Note respecting a new kind of Sensitive Paper”. By Henry Fox Talbot, Esq., F.R.S.
The method of preparing the paper here referred to consists in washing it over with nitrate of siver, then with bromide of potassium, and afterwards again with nitrate of silver; drying it at the fire after each operation. This paper is very sensitive to the light of the clouds, and even to the feeblest daylight.
The author supplies an omission in his former memoir on photogenic drawing, by mentioning a méthode he had invented and practised nearly five years ago, of imitating etchings on copper plate, by smearing over a sheet of glass with a solution of resin in turpentine, and blackening it by the smoke of a candle. On this blackened surface a design is made with the point of a needle, the lines of which will of course be transparent, and will be represented by dark lines on the prepared paper to which it is applied, when exposed to sunshine. The same principle may be applied to make numerous copies of any writing.