The first photographic positives were contact printed by sunlight from paper negatives on to Talbot's photogenic drawing paper, but usually fixed with Herschel's ‘hypo’ rather than Talbot's common salt solutions. These brown, plain-paper images had clear highlights, but if imperfectly washed out, residual thiosulphate promoted conversion to silver sulphide. The process was used from 1839 until albumen printing was introduced in the 1850s; a significant example is Talbot's Pencil of Nature. The ‘alternative process’ revival includes salted-paper printing, but modern practitioners employ gold toning to improve image colour and stability.
— Mike Ware
Bibliography
- Ware, M., Mechanisms of Image Deterioration in Early Photographs (1994)
