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Document number: 3932
Date: 12 Sep 1839
Dating: answered 4 Dec 1839
Recipient: HERSCHEL John Frederick William
Author: TALBOT William Henry Fox
Collection: Royal Society, London
Collection number: HS 17:297
Last updated: 20th February 2012

Lacock Abbey
Sept. 12. 1839

Dear Sir

I am much obliged to you for the description of your new method of making a picture on glass. <1> Do not publish it at present, for the following reason. Some one <2> has lately taken out a patent for improvements in photogenic drawing; I am not acquainted sufficiently with the facts, to be able to judge whether he has any fair right to do so, i.e. whether he has himself invented anything new, or only intends to reap what others have sown; but having conversed with a lawyer on the subject I find there is nothing to prevent him from monopolizing the Daguerreotype (in England) if he is so disposed. Now, until he enrolls his specification, which he may delay 5 months longer, he is at liberty to claim as his own any improvement that you or I or any one else may publish, and prevent us from employing it without his permission. Those things only are safe, which were published previously to the date of the patent. <3>

Such is the state of the law at present, and there is no help for it, that I know of, it behooves us therefore to describe no new process, applicable to the art, before next year.

Among various speculations which I had noted down in my journal, respecting the probable nature of the Daguerreotype I find one that came pretty near the mark: viz. to expose a silver plate to vapour of iodine (for this part of the process I have been acquainted with, more than a twelvemonth) and then, to make the photographic picture on this plate, and place it in a galvanic battery, so that it should be one of the poles of the battery. I then expected that if the electrolyte were a solution of silver, the metal would precipitate more abundantly on some parts of the plate than on others; & thus render the picture more visible, & also fix it; but I never had leisure to try this experiment. <4>

I think it would be very desirable to transmit to M. Biot <5> for insertion in the Comptes Rendus, an account of your recent observations on the spectrum. Would you like me to draw it up & send it, along with some observations of my own? In that case, I should wish to have a correct account of the paper which you sent to the B. Assocn at Birmingham <6> on the subject. It is one of the greatest interest & offers a wide field for speculation.

I have discovered a method of acting on glass, more convenient than fluoric acid, which if you like I will communicate. The fluoric vapours I believe are very noxious.

The whitening power of sunshine on iodized paper, has been published by M. Lassaigne (I think) at Paris, and Dr Fyfe <7> in Scotland. It is a most inconvenient property, for in consequence of it, it is difficult so to fix a photograph with iod. potass. as to resist prolonged exposure to light. If framed & glazed, on week’s exposure to daylight is injurious. Some indeed remain unaffected, but its difficult to say on what their permanence depends.

I have kept some photographs 4 or 5 months in a portfolio wch still retained a ground of the deepest black, yet one day’s exposure to light destroyed the blackness & reduced it to brown. The whitening power is not energetic enough to be employed directly to obtain the lights & shades in their proper place, in working [with?]<8> the Camera Obscura.

I remain yours very truly
H. F. Talbot


Notes:

1. See Doc. No: 03931.

2. On 14 August 1839, patent agent Miles Berry obtained a Writ of the Privy Seal for a New or Improved Method of Obtaining the Spontaneous Reproduction of All the Images Received in the Focus of the Camera Obscura, specification to be enrolled six months later. Berry was acting on behalf of Louis Jacques Mandé Daguerre (1787–1851), French artist, showman & inventor who wished to patent his invention in England. The patent was so general that it would have included improvements to photogenic drawing as well as the daguerreotype.

3. WHFT suffered several frustrations under the arcane English patent system, and this delay was one of them. See the discussion in Larry J Schaaf, Out of the Shadows: Herschel, Talbot, & the Invention of Photography (London: Yale University Press, 1992), p. 88.

4. In his research notebook P, on 16 August 1839, just after the disclosure of Daguerre’s process, WHFT speculated that in the Daguerreotype “a momentary exposition ought to produce a nascent effect, however small, not mathematically null.” Among the various thoughts for making this visible was the idea that ‘perhaps the galvanic action of the part acted on by light would be different, so that when immersed in some metallic solution, more metal would be deposited on that part.” See Larry J Schaaf, Records of the Dawn of Photography: Talbot's Notebooks P & Q (Cambridge: Cambridge University Press, 1996), p. P97.

5. Jean-Baptiste Biot (1774–1862), French scientist.

6. John Frederick William Herschel, ‘A Letter to the Rev William Whewell, President of the Section on the Chemical Action of the Solar Rays’ British Association Report for 1839 part 2, 1840, pp. 9–11.

7. Jean Louis Lassaigne (1800–1859), and Dr Andrew Fyfe (1792–1861), both explored methods of making direct positives employing this trait. Dr Andrew Fyfe read an extensive paper ‘On Photography’ before the Scottish Society of Arts in three sessions, on 27 March and 10 and 17 April, 1839. See the Edinburgh New Philosophical Journal, v. 26 no. 53, July 1839, pp. 144–155.

8. Text cut away under seal.

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