N S Maskelyne Esq

London
28 Nov 54

D^r Sir

I rec^d your 2 letters ^<1> for w^ch I am much obliged – My Sol^r will not trouble you to come to Town on purpose, but if you should happen to be in Town he would be glad to see you, his name is J. H. Bolton ^<2> Esq
and he lives at N^o 1 New Square Lincoln’s Inn. ^<3> His chief motive for wishing to see you is that it is contrary to his practise to call any witness whom he has not seen and conversed with. But he thinks your testimony ^<4> which I gave him today very satisfactory – Your are aware it is only for the private instruction of Counsel that they may know what questions to ask –

There is one point to which I would advert. Your say that you learned the art from my words as copied in a handbook – A quibbling objection may be raised that the handbook may have copied inaccurately – I very much wish therefore that you would make a picture or two from the specificatⁿ itself, a copy of which I will send you, for I forget whether I have done so already or not. I would wish you to follow it exactly – You will observe that I prescribe

(1) to excite the iodised paper with gallonitrate
(2) to let it rest ½ minute
(3) to dip it in water.
(4) to dry it with blott^g paper lightly.
(5) to dry cautiously at the fire, or else to use the paper moist provided it is used immediately.

The dipping must be into pure water of course, or at least into water containing no injurious impurity. By dipping, I understand, merely into the water & out again, averaging from 3 seconds to 5 of immersion. The affinity of Gallonitrate to iodide of silver is so great, that the water only removes the superfluous or uncombined particles of the gallonitrate which is just what is requisite. A long immersion would remove too much of it –

The second part of my invent^{n <5>} described in the specificatⁿ You probably never practised. It gives a positive picture at once. I found that the invisible image could be made to appear either negative or positive. The latter (as a scientific fact) is still more curious than the former but it never came to practical use

1^st for the reason I give, viz. it is 10 times slower than the other, too slow for portrait taking.
2^d because the positive pictures are unique, whereas from the negatives many positive copies can be printed.
3^d because it reverses the image from Right to Left –

I do not think it necessary that you should now test the accuracy of this 2^d part of y^e invention w^h you never practised, only I should wish you If you do make any exp^ts on y^e subject, to go through with them, as it is a process of nicety & skill, and at first you might not obtain a good result –

Yours Truly
H. F. Talbot

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Notes:

1. Doc. No: 07066 and Doc. No: 07067.

2. John Henry Bolton (1795–1873), solicitor, London.

3. One of the four Inns of Court, ‘colleges’ of barristers in England.

4. Story-Maskelyne had been asked to be a witness for WHFT [see Doc. No: 06991] in the trial Talbot v. Laroche in which he sought to prove that the collodion process was covered by the Calotype patent. The trial took place from Monday 18 to Wednesday 20 December 1854. In 1852 WHFT had thrown open his photographic patents as far as amateur photography was concerned, though he retained them regarding professional portraiture. He won several injunctions against professional portrait photographers, and in 1854 he sought to obtain one against William Henry Silvester, known as Martin Laroche, a professional photographer who took portraits using the collodion process. He then found himself having to defend his right to his patents and even his claim to the invention of photography on paper.

5. WHFT’s direct positive process.