link to Talbot Project home page link to De Montfort University home page link to Glasgow University home page
Project Director: Professor Larry J Schaaf

Back to the letter search >

Result number 3 of 3:   < Back     Back to results list   Next >  

Document number: 6287
Date: 07 Jan 1850
Harold White: 7 Jan 1850
Recipient: TALBOT William Henry Fox
Collection: British Library, London, Manuscripts - Fox Talbot Collection
Collection number historic: LA50-3
Last updated: 24th December 2012


Some years ago I had the honour of addressing you on some improvements I suggested on Photography, and you then took some notice of my experiments in Gelatine. I afterwards proposed some farther trials on Glass, which I instituted before the discovery of Collodion. These proved unworthy of any notice.

Nothing disconcerted, I have followed up various plans of my own, whenever opportunity or scanty means allowed. I again beg to submit a different series, the value of which may be questionable, but which I humbly think, merit some consideration – No one has seen my experiments – they are untold to any one – this is the first opportunity I have taken of divulging them – and previous disappointment renders me less sanguine. May I ask you, is it desirable to change the first [illegible deletion] negative Calotype on paper into a positive on Glass – without the aid of light – so that the positive should be capable of reproducing other glass or paper positives

If it be – I can do it – and the negative Collodion pictures – and even the Daguerrotype [sic] may be similarly multiplied – with different modifications – The hues and tints may be varied I should say, ten times, and the process is simple.

You may easily test the value or worthlessness of my results – as I cannot for want of means, carry out the discovery (if it be one) and am wishful to pass on to another promising agent, viz. Chlorine. If this be of no value, perhaps you will kindly tell me, and leave me the chance of following it up, when better times come on.

Now for the basis of my operations. An even coating of Starch is spread on the plate. We all know this is coloured blue & when dry (reddish or other hues predominate) by Iodine. A dry negative – brought out by Sulphite of Iron (in preference perhaps to Gallic Acid) would not effect it, but a wet one would absorb all the Iodine where the Silver was darkest – and proportionately throughout the to the depth of tints – would be the gradations of colouring on the Glass. Much depends on the strength of the Iodine [illegible deletion] colouring, but if it be too deep, it is easily softened down by immersing the incomplete positive in [illegible deletion] very weak Hyposulphite of Soda. This experiment is simple and easily produced –

If you send me a weak small negative or two, that may be valueless to you – I can give you specimens of two or three kinds, that will convince you, that this is but a step to other attainments, that may prove to be of intrinsic value.

The blue of the Iodine need not remain so, as brown, black, red, orange, & other colours may easily replace it –

I think, there is a possibility of permanent fixedness, which some complain is not to be found, in ordinary proofs.

Starch is colourable by water colours, & oil colours, and would be available in your hands, for portraits of a high order.

Were transparency is not requisite & some opaque ground is formed on Glass by precipitation of Sulphite of Barytes, and a thin coating of Starch is run over it.

I knew ten years since that Iodine or Bromine in vapour would obliterate a negative, beginning with the weakest tints – A Gutta Percha coating, that had been impregnated with Iodine – would in like manner give up its Iodine in proportion to the Silvering. So would Collodion, and the yellow tinting would absorb the chemical rays, so as to admit of the printing being done – But from such, the Iodine is fugitive. It is not so with the starch.

If Collodion negative or positives are preferable – they too extract the iodine from the Glass – after some preparation.

The Daguerrotype must be treated in another way altogether, and can be converted into a good negative on Glass, with beautiful details.

I trust there is no want of due modesty in the liberty I have taken to address you again. There may be something suggestive in my humble efforts, which may not be unacceptable even to a proficient in the Art – If it were pardonable I might myself, suggest some-thing new, even from this first stage of progress – With 3 weeks on my hands, I might add something to the almost unlimited knowledge you possess. If you ask for specimens, please put me in possession of a few waste negative, that will admit of being tested, so as to satisfy you, that your own materials have been tested. The negative must have been brought out by Sulphite of Iron, Gallic Acid or vapour of Mercury.

Probably I may be a visionary, or a follower up of useless subjects, in that case, I must apologize for trespassing on your time, which I will promise not to repeat – At all events, you are not, so can more readily show other men, detect my fallacies, yet and perhaps they deserve Knowing to be discarded. My character as a Teacher has always been that of an unpretending, but practically Kind, and it is but at intervals I could do anything in this fascinating Art.

I am Sir, Yours most respectfully
A McFarlane

If you should trouble to reply, it will find me at Mr Ambler’s, Temperance Hotel,
Thornton Road Bradford Yorkshire

To H. Fox Talbot Esqe

Result number 3 of 3:   < Back     Back to results list   Next >