TALBOT7059

Mr Maskelyne

Lacock
13 Nov 54

D^r Sir

Thanks for your very friendly letter ¹ – I shall not be able to call at Oxford ² in my way to Town, being pressed for time at present, but I will write again from London and arrange for meeting either there or at Oxf^d.

I have been furnished with the particulars of the objections which will be made to my patent, on the trial. ³ Among other things I find that the Rev^d M^r Reade claims to have invented the Calotype process and published it 2 years prior to the date of the patent. The evidence for this, consists in a letter from M^r Reade to M^r Brayley ⁴ which the latter read at a public lecture on the (then new) art of Photography in 18 439

This was 2 or 3 months after I had published my first photographic process. ⁵ And M^r Brayley’s lecture ⁶ was upon that process, with suggestions for improving it. Among these was M^r Reade’s, which divested of superfluous words amounted to this – Let common writing paper (in its ordinary state) be wash’d with gallonitrate of silver (he uses the substances separately but they are better combined) then, says M^r Reade, a paper is obtain’d that is very sensitive to light.

This he claims as being identical with my calotype process. In the first place his letter, orally delivered in a lecture, was never published before the date of my patent nor until 6 years & a half afterward. In the next place my Calotype process consists in washing iodised paper (iodide of silver) with the gallonitrate, and then (which is most essential) developing the latent image with a 2^d application of the gallonitrate aided by warmth. The existence of the latent image was unknown to M^r Reade. ⁷

These details are doubtless perfectly well known to you, and I have no doubt you consider as I do, that M^r Reade’s process was only an approximation toward a true system of photography – a step in the right direction, no more. But on receiving notice that this claim would be urged it occurred to me to try M^r Reades process, and I found upon trial that it failed entirely. A piece of common paper, & a piece of iodised paper, were excited with the same gallonitrate of silver & exposed in a camera to receive the photographic image of a marble bust. for After the usual number of seconds had elapsed the two papers were withdrawn when the iodised paper was found to have received a good image, while M^r Reades paper was perfectly blank.

I know not whether you have got your photographic apparatus with you at Oxford, if you have, perhaps you will try the little experiment above described as I should be very glad to have corroborative evidence of the fact to place before the judge and jury – Last summer I noted down several observations of yours on the Collodion process &c &c. I will send you a copy of these notes to know if they are correct, but will take another opportunity of doing so, in order not to make this letter too long

Believe me D^r Sir Yours vy Truly
H. F. Talbot

My address is the Athenæum ⁸