Q. Ann St <1>
March 15. 1839
Dear Sir
I was sorry not to have heard your paper which I understand was read to the R.S. last night.<2> – Would you like to send some specimens of your engravings to Baron Humboldt <3> & the Berlin philosophers; – I received a letter from him today & am going to answer it by Tuesday’s post. <4> As you told me that you had not quite succeeded in fixing with common salt I enclose a fragment done in that way; and 2 others (yellow) done with iodine. I have found the Bromide of silver very sensitive, & intend saying something respecting it in a paper to the R.S. next week. <5> I enclose a scrap, exhibiting 4 different states of the Bromide of which one is nearly invisible (exactly as with the Chloride & iodide) Consequently a stronger solution of Bromide Potash will fix a drawing made with Bromide Silver.<6> At least I presume that this consequence may legitimately be inferred.
I send a few specimens of this sensitive paper. <7> If they have lost their virtue, another wash of nitrate of silver will probably restore it.
Yours most truly
H.F. Talbot
Notes:
1. Queen Ann Street, London.
2. John Frederick William Herschel, ‘Note on the Art of Photography or the Application of the Chemical Rays of Light to the Purposes of Pictorial Representation’, read before the Royal Society 12 March, 1839, not submitted for publication. For a full transcription of Herschel's original paper, see Larry J. Schaaf, ‘Sir John Herschel’s 1839 Royal Society Paper on Photography’, History of Photography, v. 3 no. 1, January 1979. pp. 47–60.
3. Alexander von Humboldt (1769–1859), German scientist.
4. See Doc. No: 03830 for the letter sent to WHFT. The reply, mentioned in Doc. No: 03843, and enclosed photographic specimens made by both WHFT and Herschel, have not been located.
5. On the 21 March, WHFT presented the process of his Bromine paper to the Royal Society, it was published as ‘Note Respecting a New Kind of Sensitive Paper’, Proceedings of the Royal Society of London, v. 4 no. 37, 1837–1843, p. 134.
4. Talbot discovered his first fixer in 1834 when he observed that a weak solution of table salt sensitised the paper whereas a stronger solution afterwards made it less sensitive to light. The actioin of potassium bromide was an exact parallel to this.
7. Enclosures not located.