Slough.
April 27/39
My dear Sir
I sit down in great haste just to mention to you a step I have made this morning of a very decided character with respect to the discovery of a paper even more sensitive I think than the Bromine Specimens you sent me, with the addition of this valuable property that the Bromine paper wants viz: that the tint goes on deepening in arithmetical progn with the time, whereas yours comes to a still stand very soon.– It is moreover prepared with materials of the most ordinary and abundant description, without Bromine, or any chemical rarities.–
I have I annex a specimen of this paper and also of a photograph done with it in 60 seconds exposure to the light of a cloudy sky with occasional glimpses of sun just enough to cast a shadow <1> –
To try its efficiency in the Camera obscura, I put up a specimen of the paper in the early part of the day while the sky was densely clouded, as it continued to be the whole time of exposure. In 45m The picture was formed & more intense than any I have yet procured with the Camera in a whole day.– In 2h The picture was strongly and decidedly coloured and quite as complete as could be desired – as to sharpness &c
The day growing brighter latterly, I placed another paper in the Cama – In 10m The picture though faint was distinctly outlined and might serve as a traveller’s sketch.
The paper in 3sec exposure to the gloomy light of the the cloudy sky was sensibly discoloured.– In less than 1s in a sun enough to cast a feeble shadow, the discoloration was decided & even strongly marked.– In 20s in such a Sun the tint is that of ordinary writing ink when smeared with a feather on paper. I think therefore we are safe in declaring that the process of photography is now placed within the reach of every body – is quicker than copperplate printing (ie. than the more elaborate sorts) – is susceptible of quite as great delicacy as the most finished copperplate work – and is quite available for self registry of all sorts.
I remain my dear sir yours very truly
JFW Herschel
[draft] <3>
Draft of letter to Talbot sent with alterations
April 27/39
My dear Sir,
I sit down in great haste just to mention to you a step I have made this morning of a very decided character which relates to the discovery of a paper even more sensitive I think than your Bromine paper at least than the specimens you sent me with this valuable property which that wants viz: that the tint goes on deepening in arithmetical progression with the time whereas your Bromine paper comes to a still stand.– I enclose you a specimen.– I put up in a camera obscura just 45 minutes ago, a [missing page] and although the day is abnorm uniformly and densely cloudy, there is already on it a picture more forcible than any I have yet seen produced by the camera. In 10s 3s exposed to daylight of the present sky it gives a sensible discoloration – In less than 1s in such a sun as just at this moment shines out the tint is very decided & even strong. NB. The sun is barely enough to cast a shadow – In 20s of this Sun the tint is that of ink quite as dark as this writing. [NB The ink has darkened since]
It may be prepared with a certainty of not discolouring in the dark. [No – it discolours after a long time – but.]
I have just placed for trials sake a specimen on a photographing frame and I enclose the results after 60 seconds exposure to a sun barely sufficient to cast a shadow – Taking this as an average Day in this climate I think we are safe in declaring the process to be as rapid as copper plate printing i.e. of elaborate work.
I hope you got my last specimens. I wish I were not hurried to Paris as I am convinced that one or 2 days more on this new scent would have led me to some most valuable conclusions.– For the present therefore, I must conceal my process but NB. The Materials are all of the most ordinary & abundant sort No Bromine, or any chemical rarities
Yours very trly
JFW Herschel
Notes:
1. This was the first communication of Herschel’s ‘plumbozoic’ paper no. 1038. Enclosures not located.
2. Herschel travelled to Paris on 30th April 1839, where he met Louis Jacques Mandé Daguerre (1787–1851), French artist, showman & inventor, and saw his first daguerreotypes.
3. Written in Herschel’s hand.