Ordnance Survey Office
Southampton 14th May 1860
My dear Sir,
I have great pleasure in sending you some specimens of Photo-zincography. This . art promises to be of great importance to the public for the purpose of making fac-similes of ancient M.S.S. or rare works either in type, or engraved in outline. We have not attempted to copy any thing in which there is a gradation of shade, and the process is not suited for it. The process consists in this, a highly intensified negative is first taken on glass by the collodion method, a print is then taken on a sheet of very thin paper which has been washed over with a saturated solution of the bichromate of potash and gum, and dried. After exposure for one or two minutes, the Bichromate positive is laid on a sheet of zinc which has been previously coated with lithographic ink, and passed through the press. The paper is then submerged in a shallow vessel of hot water with a little gum in it, and the water is agitated and the paper gently brushed over the paper to remove the soluble bichromate, and the ink attached to it, this leaves the insoluble portion with the ink on it, or in other words a positive picture charged with ink, and ready for being transferred either to zinc, stone, or to the waxed surface of a copper plate – I prefer zinc for many reasons, and an examination of the specimens sent will enable you to judge of the degree of perfection to which we have already brought this art. We could copy any M.S. or rare book at a cost of half-penny a page – I have been anxious to give the fullest publicity to what we have done in this way, and I have therefore given an account of it, with a specimen, in my Annual Report to Parliament, and you will see an account of it, both in the Photographic News, and the Photographic Journal, I believe a full account will appear in the next number of the latter which will come out this week –
I am much obliged for the specimens of photoglyphic engraving, and it appears clear to me, that if you confine yourself to the copying of lines, you can produce very perfect copies, and they will be sharper and clearer than by photo-zincography –
But I cannot think that your Camera is exactly suited for this class of work – we have an 8 inch lens for ours, and you will see that we produce photographs of folio sized drawings, of the exact same dimensions as the original.
The engraving of Furness Abbey proves beyond doubt that you will also succeed with the half tints –
Has any account of your process been yet published? if so I wish to have a reference to it. I hope you may be able to pay this Estbt a visit, we have many things which will interest you here.
Yours very truly
Mr Sidney Herbert is the Secretary of State for War, and the head of this Dept
H. Fox Talbot Esqre