Lacock Abbey, Chippenham
Aug. 1. 1843.
Dear Sir
I think you will do well to take two Camera Obscuras with you, one of them small, of the size of mine, which works quickly & makes beautiful vignette pictures, the other large - I recommend you to procure them of Charles Chevalier, 1 in the Palais Royal, eastside, No 163. He makes the large ones to fold up for travelling - He will take at least 4 or 5 days to make the paperholder &c so that you should lose no time in ordering it. I recommend you to purchase the necessary chemical ingredients of Garden, Chemist, 372 Oxford St. You should have a small box on purpose to hold the bottles, like a medicine chest. On the other side I have added a list of things wanted. I regret the shortness of the time, which prevents our assuring ourselves that everything is in order. But as you succeed so well with the moist Calotype 2 paper, I should be glad if you would practise on the dry, because it is in that state you will generally wish to use it in Lycia.
Memoranda
Let NS express Nitrate of Silver, 100 grains dissolved in 2 ounces of water. and ⅙ part of Acetic Acid added.
- G - Gallic acid, fill a small bottle ¼ full of it, then pour cold water on it, and replenish as you use it with water. The greater part of the acid will lie at the bottom undissolved; when nearly gone, add more.
Let GNS express 1 part of NS added to 1 part of G - I call this the Gallo Nitrate of Silver - It will not keep good more than ½ an hour.
To excite the iodised paper it is washed with GNS, and then is called Calotype paper.
To make dry Calotype paper several recipes may be used, the following is one I prefer - Add 1 part of NS to 10 parts of G, wash the iodised paper with this, blot it gently, and dry it in the dark, in a current of warm air, or held before a dull fire. Kept in a press it will last good some days. It is ready at any moment to receive an impression - The impression need not be rendered visible or brought out for some hours afterwards To bring it out, wash it with a mixture of 1 part NS and 1 part of distilled water. But note, that a very strong impression should be brought out with a weaker solution of silver, viz. 1 part of NS added to 2 or 3 or even 9 or 10 parts water. This is an affair of the artist's judgment & discretion.
Things wanted
Nitrate of Silver, in crystals (always dissolve this in distilled water, but it is not requisite to use distilled water for any other part of the process)
Bromide of potassium, in crystals.
Acetic Acid, having a strong pungent smell.
Distilled water.
Gallic acid in crystals.
Iodide potass. in crystals.
A good many paintbrushes - which should be kept very clean.
Small saucers.
white blotting paper, a good deal of it.
Small pair of scales, weights of 100 grains, 50 grains &c. &c.
an ounce measure divided into parts.
a drop measure divided into 60 parts
I enclose a brief account of the Calotype process which I presented formerly to the Royal Society.3
The negative pictures only concern you at present - The use of the Acetic Acid is to keep the white parts of the picture clean and white if therefore they are darkened, add more acid to your GNS, yet not too much. The only deleterious substance is the NS, the best remedy when the fingers are blackened with it is to wash them in a strong solution of iodide potass. and expose the hands as much as possible to day light.
Believe me Yours very truly
H. F. Talbot
C. Fellows Esq
30 Russell Square
London
4
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