[draft:]
Carpml
20 Apr. 56)
I wsh t ask yr opnn on ye follg pat in case you are able t form a strong opinn 1 way or ye other, on my primà facie [illegible deletion] respectg it –
I have a patt for engravg a photogrc “improvemts in engravg” – This invn reposes on ye follg fact discd by myself. viz.
(1) Gelatine mix’d wth BC. pot ^and dried in the ^dark is soluble in water. But
(2) But a very short exposure to daylight render it insoluble in water. whence I ob deduced my invn wch consists of 2 parts.
Part 1st
(1) a plate of steel is coated with ye above mentd substce in ye dark.
(2) an a photogrc image is impressed upon it, with a cam in ye ordy way viz. with a Camera or otherwise.
(3) the plate is dipped into water – wch dissolves ye gelatine in those parts only, where ye light has not acted.
(4) the plate is dried, and then has on it a [illegible deletion] visible photographic picture – Also the gelatine being removed by the water in certn places, there is conseqly a difference of level in ye picture, altho’ ye steel plate underneath is level.
[all this was my inventn – ] I did not confine myself to steel plates, but have indicated its+
+ applicty to zinc plates & lithogrc stone.
Second part
an etching liquid is now poured on, incapable of penetrating dry gelatine. Consqly the steel plate is etched by it, wherever the gelat. has bn removed: but not elsewhere. –
[This part ^was also my invn]
Such is my process wch ansrs very well in practice. I print from my etchd+
+ plates by the usl mode of copperplate printing.
Now then ^to my question.
Certn persons have taken out a patt for impvements in ^photc engraving
They proceed as folls
First they take the whole of my 1st part (admitting that they have borrowd it fm me). But they use instd of a steel plate, a plate of glass or anything.
Then, the They do not use the 2nd pt of ye invn But they take advantage of ye diffce of level in my photc pict. and electype it. Thus they obtn a copperplate presentg a simr photc pict. Fm wch they strike off impressns in ye usl mannr of copperpl. printg.
I request to know your opinn whether their patent is not an infrgemt upon mine?
I believe you have got the specifns of my patt wch bear date 3 yrs ago last November, if y like to refer t it.
[expanded version:]
Carpmael
20 April 1856
I wish to ask your opinion on the following patent in case you are able to form a strong opinion one way or the other, on my primà facie [illegible deletion] respecting it –
I have a patent for engraving a photographic “improvements in engraving” <1> – This invention reposes on the following fact discovered by myself. viz.
(1) Gelatine mixed wth Bichromate of Potassium and dried in the dark is soluble in water. But
(2) But a very short exposure to daylight render it insoluble in water. whence I observed deduced my invention which consists of two parts.
First part
(1) a plate of steel is coated with the above mentioned substance in the dark.
(2) an a photographic image is impressed upon it, with a camera in the ordinary way viz. with a Camera or otherwise.
(
3) the plate is dipped into water – which dissolves the gelatine in those parts only, where the light has not acted.
(4) the plate is dried, and then has on it a [illegible deletion] visible photographic picture – Also the gelatine being removed by the water in certain places, there is consequently a difference of level in the picture, although the steel plate underneath is level.
{all this was my invention – I did not confine myself to steel plates, but have indicated its applicability to zinc plates and lithographic stone.
Second part an etching liquid is now poured on, incapable of penetrating dry gelatine. Consquently the steel plate is etched by it, wherever the gelatin has bee removed: but not elsewhere.– {This part was also my invention}
Such is my process which answers very well in practice. I print from my etched plates by the usual mode of copperplate printing.
Now then to my question.
Certain persons <2> have taken out a patent for improvements in photographic engraving. They proceed as follows
First they take the whole of my first part (admitting that they have borrowed it from me). But they use instead of a steel plate, a plate of glass or anything.
Then, they They do not use the second part of the invention. But they take advantage of the difference of level in my photographic picture and electroype it. Thus they obtain a copperplate presenting a similar photographic picture. From which they strike off impressions in the usual manner of copperplate printing.
I request to know your opinion whether their patent is not an infrgement upon mine?
I believe you have got the specifications of my patent which bear date three years ago last November, if you like to refer to it.
Notes:
1. Patent number 565, 29 October 1852.
2. The Patent Photo-Galvanographic Company (commonly, The Photogalvanographic Company) was based on the work of Paul Pretsch (1808–1873), Austrian photographer & inventor and former Manager of the Imperial Printing Establishment in Vienna. Located in Holloway Road, Islington, London, from 1856-1857, Pretsch took over as manager and Roger Fenton (1819–1869), photographer & lawyer, was a partner and their chief photographer. Starting in late 1856, they published a serial portfolio, Photographic Art Treasures, or Nature and Art Illustrated by Art and Nature, illustratated with photogalvanographs derived from several photographer's works. Photogalvanography was uncomfortably closely based on elements of WHFT’s patented 1852 Photographic Engraving but, unlike Talbot, the plates were heavily retouched by hand. Compounding the legal objections of Talbot, their former manager, Duncan Campbell Dallas, set up a competing company to produce the Dallastype. The company collapsed and near the end of 1860 Pretsch, out of money, allowed his patent to lapse. A public appeal was launched in 1861 to assist him but he returned to Vienna in 1863 in ill health, going back to the Imperial Printing Establishment, but finally succumbing to cholera.