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Document number: 4577
Date: 15 Aug 1842
Recipient: TALBOT William Henry Fox
Author: PLAYFAIR Hugh Lyon
Collection: National Science and Media Museum, Bradford
Collection number: 1937-4907
Last updated: 13th March 2012

Calotype as attempted @ St Andrews up to 15 August 1842<1>

1st The best of Whatman’s <2> paper has been used

2d– Chrystalld– Nit-Silver 100 Grains in 6oz distilled water

3– Iodide of Potassm. 500 Grains in 1 Pint Do –

4– A Saturated Soln– of Gallic acid

5– 100 Grains Chrysd. Nit-Silver in 2oz distilled water & add to this Soln– 2/3 of th Bulk of Acetic Acid –

6 Bromide of Potassm.100 Grains to 8oz water

7 Nit Silver 80 Grains to 1oz water

8 Take 1 Part of a Satd. Soln– of Salt to 8 Parts Water

The above are the ingredients used in the Process,, –

Manipulation 1 Spread the Paper with a Soft brush wt No 2 Mixture Rubbing it in well & then dry it on a cloth over Stove in a dark Room.– 2 When dry, immerse the paper into Soln. No 3 @ 65o Temperature leaving it in 1 minute – if at 60o leave it in 11/2 minutes “– Then plunge the paper into cold water & then into a second basin of clean water so as to Remove the Iodide Completely & finish drying with blotting paper & then expose it over the stove on the Cloth frames,, – N.B. I have always found it beneficial to expose the paper thus prepared to bright Sun light before using it & farther that the paper improves when Kept for a week or two ,, –

3 When about to use the paper the Galls Nitrate is prepared – we mix equal bulks of No 4 & 5 & add thereto a bulk of water equal to the volume mixed Soln i.e.

20 Drops Nitrate

20 “ Gallic Acid 40 “ Water Then spread the Iodised paper by Gas Light wt. this Galls Nitrate & after allowing it to Soak for 1/2 a Minute, blot it in Clean blotting paper & put it into the Camera. – 4 In clear Sunshine we find the time Reqd from 20” to 30” of the paper is good but never less. – 5 After withdrawing the paper from the Camera which has been used without any glass intervening – we use the Soln– of Nit–Silver & Gallic Acid undiluted – we spread this over the picture & expose it to heat over a stove in a dark room

If the Picture does not come out Readily – we give another washing & a third if Required –,, –

Fixing Process

The Picture if worth preserving is then plunged into cold water & dried with blot paper, & then spread over with a Soln– No6 then plunged again into water – blotted & dried,,


I have never succeeded in the process described by Mr Talbot of dipping the paper in Water after spreading with the Gallo Nitrate but have adopted in lieu thereof the diluted Galls Nitrate as above Mentioned ,, –

Thus ends the Negative Process

Positive Copies

Select good writing paper – dip it into a Satd. Solution of Salt & 8 parts water for a few seconds – & then use blot paper.–

When about to use this – wash it over with Solution No.7 & dry it at a stove or distant fire ,, –

The copies are exposed under glass to the Suns light in the usual way. –

When suffiecently done – they are washed in cold water. so as to take out the free Nitrate Silver – they are then blotted & Washed over with Solution No6

Again plunged in water & dried at the fire,, –


We cannot succeed by the above process either in obtaining a clear sharp picture (such as taken by Mr. Talbot) or of fixing them with any degree of permanency And

Humbly Pray for further information as a Reward for most laborious application & disappd. expectation for upwards of 12 Months,, –

H.L. Playfair

My Dear Sir David <3>

If Your friend Mr. Talbot will condescend to peruse these notes & give us any new light on the Subject – we may go on … But with the present light we cannot advance one step & I Regret to say that the Daguerreotype must have infinitely the ascendancy unless this Art is more easily attainable – With the other I never have a single failure – with this I never have anything else

V s Y
HL Playfair


1. Although transmitted through their mutual friend, Sir David Brewster (see below), this description was intended for WHFT's purusal and comment.

2. James Whatmans Turkey Mill paper was favoured by watercolourists and was the most suitable paper available for early photography. Rag-based, its wove surface (as opposed to the more common chain-laid) provided a uniform base for prints and a patternless density for negatives. Its gelatin sizing (compared with the rosin sizing used for continental papers) was ideal for photographic chemistry. Being made by hand, there were variations between batches even in this high quality paper, and certain years were sought after. It was generally watermarked with the year of manufacture.

3. Sir David Brewster (1781–1868), Scottish scientist & journalist.

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