With respect to the claim<2> for the use of “liquids” I have enquired of Mr Henneman<3> as a practical Photographer, whether he thinks that any person takes the photographic portraits without developing the image by immersion in a liquid? He says no one does, for in practise i[t] cannot be dispensed with.
I asked what liquids are practically employed he says that in paper photographic portraits the object being to obtain in ye 1st place a negative image on glass, gallonitrate of silver is the liquid generally employed, which is the one originally described by me, altho’ some persons prefer to use pyrogallic acid mixed with nitrate of Silver. He thinks there can be no doubt of the Employment of it by Laroche.<4>
The use of the salts of iron is chiefly confined to the production of positives on glass, or amphitypes as I call them<5> – My receipt<6> for making them in my last patent <7> indicated Sulphate of iron –
H. F. Talbot
1. The Athenæum and (London) Literary Chronicle, London.
2. See Doc. No: 07095. In the trial concerning his patent, Talbot v. Laroche, WHFT sought to prove that he had invented the Calotype process and that the collodion process was covered by the Calotype patent, and was thus not a new invention. The trial took place from Monday 18 to Wednesday 20 December 1854, and in it WHFT found himself having to defend his right to his patents and even his claim to the invention of photography on paper.
3. Nicolaas Henneman (1813–1898), Dutch, active in England; WHFT’s valet, then assistant; photographer.
4. William Henry Silvester, whose professional name as a portrait photographer was Martin Laroche.
5. See Doc. No: 06525 [which also refers to the use of ‘salts of iron’]. WHFT originally coined the name amphitype for a process devised by Sir John Frederick William Herschel (1792–1871), astronomer & scientist in March 1843 – see Doc. No: 04784 – but during the 1850s the term was used as an alternative for ambrotype, a collodion direct positive.
6. i.e. recipe or formula
7. Patent No. 13,664, enrolled 12 June 1851, for both the amphitype and a camera for field processing, it was finalised 11 December 1851.