| Description | Full copy of patent specifications for the 'improvements in obtaining pictures on representations of objects', dated 8 February 1841.
Signed Poole & Carpmael, patent lawyers, Old Square, Lincolns Inn.
Defines preparation of the "iodised" paper which becomes "calotype paper", including detailed list of chemicals and instructions; the fixing process; the mode of obtaining positive photgraphic pictures; images on copper; obtaining very thin silver plates; transferring photogenic images.
Patent claims on the basis of employing gallic acide or tincture of galls, making photographic images visible, obtaining portrait from the life, use of bromide of potassium |