Patent copy specification of William Henry Fox Talbot 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 1841