April 1843

In the first paragraph, Puhar refers to Dr Mosre's theory of light and to Robert Hunt's theories regarding thermo-electric molecular changes on a mirrors smooth plane when in contact with an object. The end result of this contact is an impression - a picture that becomes visible if certain vapours are used. Puhar then wrote the following:

"My invention, which has been created one year ago, makes use of the following phenomena: the light is reflected from exposed objects into the Camera Obscura where it infects the molecules of a warmed and cleaned glass plate in the same way this geometric body does by contact. This infection process occurs after intentionally applying greatly heated vapours during the exposure, in my opinion lasting about 15 seconds, which are then caught only momentarily, in the blink of an eye, on the exposed places while they are undergoing condensation or electric attraction, the result being that the glass remains partially or entirely clean, in proportion to the intensity of the tones of light; this means that condensate is not created on the exposed places but rather the vapours are reflected. After this game of vapours, the picture in the Camera Obscura is fixed and you can see a fixed motif on the plate when looking at it a certain distance away against a black plate when the plate is held in front of a sunny window. The picture thus created is transparent, in the blue colour tone and not mirrored. On the other hand, it can be viewed under light as a daguerreotype as it possesses its sharpness and fidelity of colour, although in a smaller degree because it does not have its colour binding quality and due to the fact that under certain circumstances there are spots on the pictures that shine as through a fog due to improper handling.

To make a picture thus created permanent, it needs to be varnished and covered with a glass plate to protect it against humidity and dust. Such a picture can also be etched using fluoride acids.

Finally, let me mention that the entire operation and its results are based on a regular lens made from regular glass in the size of 2 inches and by using intense light."

(M. Kambič, Janez Puhar, izumitelj fotografije na steklo, 150 let fotografije na Slovenskem, Ljubljana 1989)


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January 19