SILVER PHOTOGRAPHIC TECHNIQUES IN THE SECOND HALF OF THE 19th CENTURY

In the second half of the 19th century silver photographs were made on various materials. Paper, textile and glass were most freguently used for th a t purpose. Occasionally, other less typical materials such as wood or metal were used. Photographs on these bases are found rathe r in works of amateurs th an in mass production, where paper was a dominating material. Photography of th a t time could exist on its own as a work of a rt or a produce of craftsmanship. On rare occasions it served as a base for paintings or wood-engravings. Some techniques, e.g. ambrotypography, ferrotypography, went with specific bases, while others could be excuted on various materials. In the majority of technique a silver picture was formed on a photographic emulsion or on the surface p re paring the base. In other techniques, e.g. on painting canvass, emulsion was not used; instead, the base was coated w ith a solution of photosensitive salt. Photographic emulsions and solutions for the prepa ra tion of the base were made on th e basis of proteins, colloidon, adhesive, agar-agar. Silver chloride, iodide, bromide and n itra te were employed. A silver picture was toned down in solutions of metal and nonmetal salts. This was necessary in the case of the so-called daylight papers, i.e. albumin, ” Aristo”, celloidine and salted paper. Pictures on these papers did not require chemical developing but due to an u n sa tisfactory colour they had to be toned down. The toning b ath was sometimes combined with fixation. Protos made in big qunatities in photographic shops were as a rule retouched by stippling, taching of spot covering techniques. A ready photo was varnished and put on cardboard