Athenæum Club
June 19. 1854
Dr Sir
I am going to make You a request which I hope may not be too troublesome – I am engaged in legal proceedings against a person for infringing my patent called the Calotype Photographic process. This invention I freely presented to the Public 2 years ago, reserving only one point. But the infringer being resolved to disregard my rights, I have appealed to the protection of the law. The trial will come on in the Common Pleas about the 1st of next month. I should be much obliged therefore if you would Kindly consent to give scientific evidence on my behalf, especially as my friend Herschel, whose Evidence would be invaluable, has an objection to appearing in a Court of Law and therefore it is not our intention to ask him. The points on which I would request your testimony are first, the general notoriety of the invention in the Scientific world, as attributed to me (the defendt denying that I was the inventor) Secondly – the chemical Similarity of the process called Calotype & that which Employs Collodion, both forming an image upon a surface of iodide of silver moistened with Nitrate of silver, and developing the photographic image with gallic acid. The defendt relying upon the fact that I have spoken of paper, and that Collodion is not paper, which I willingly admit but consider the point a secondary one since the Collodion acts instead of the paper, as a support to the iodide of silver – I shall be happy to send you a printed Copy of the specification and to perform any photographic experiment in your presence that you may deem requisite to enable you to form a satisfactory opinion although I doubt not but that you are perfectly familiar with the subject in all its bearings – I hope I am not intruding too much on your kindness in making this request and remain
Dr Sir, Yours very Truly
H. F. Talbot
W. R. Brande Esq