Dated May 27th, 1856.
PATENT FOR THE APPLICATION OF COLORING SUBSTANCES, OR MATTER, TO PHOTOGRAPHIC IMPRESSIONS.
Be it known that I, Giles Langdell, and Marcus A. Root, of Philadelphia, in the State of Pennsylvania, have invented a new and improved mode of coloring daguerreotype and other photographic portraits or pictures made on glass, metal or other material; and we do hereby declare that the following is a full and exact description:—
The nature of our invention or discovery consists in providing and applying both mineral and vegetable coloring matters in solution to the daguerreotype or any other photographic impression, introducing the said coloring matter either into the collodion or the developer, or by pouring upon the plate after the impression is fixed by hyposulphite of soda, or the cyanide of potassium, or by any other means.
The several coloring substances, E. G. red saunders, alkanet, dragons' blood, &c., &c., can be used separately or in conjunction or compounded with various mineral substances, or with any coloring matters obtained from other roots, woods, gums or other vegetable matter, the proportions or quantity employed being varied or regulated by the lightness or depth and strength of tone which may, from time to time, be required.
The desired or similar results may be obtained from different formulæ. The following answers for all practical purposes, but may be varied at pleasure:—
Digest for two or three days red saunders (pterocarpus santalinus) half a pound in three pints of water to which the aqua-ammonia has been added. Then pour off the solution and precipitate by the addition of nitric acid. Wash the precipitate thoroughly with water and dry it. Then dissolve it in strong alcohol and dilute with the same as required to produce the tone or tint that may be desired. Alkanet (anchusa tinctoria) may be prepared in the same way. Dragons' blood dissolved in alcohol and treated in the same manner will produce the various shades of yellow. The foregoing articles, and also madder, indigo, cochineal, and some other coloring substances both vegetable and mineral alone or combined, will produce pleasing results when applied as follows (although they may be introduced into the collodion):—
We prefer first to develope the impression, then to fix and dry it, and afterwards to flow on the toning or tinting solution, as collodion or varnish, &c., is poured upon the plate, allowing the solution to run off the corner, and then levelling the plate to make the fluid flow uniformly over and tint the whole surface of the plate evenly.