Year 1851

"Every invention, however small at the first glance, in the field of daguerreotypes needs to be checked thoroughly for it represents a contribution to the progress of our knowledge of a field where we are almost entirely without any scientific principles. This is even more necessary when it-as a surface that reacts to light-introduces a new agent capable of organically binding with most of the elements and is also capable of organic enrichment by itself. The latter applies to my own process that uses sulphur to make transparent photographs on glass plates, which has been significantly improved since its discovery eight years ago.

Of course, pictures created in this way look humble in comparison with daguerreotypes and photographs created using Talbot's process. However, since the route I have taken for achieving them is new, the pictures will nevertheless receive attention from the Academy of Sciences and even more so because the reason why my pictures look less attractive and elaborate is only a lack of resources. My process is particularly suited for distinct and architectural objects and for steel engravings, which is partly evident from the attached samples. The process is perfect for light representation of the aerial perspective; the colour tones can be arbitrarily modified in certain cases and the unique translucent azure is clearly distinguishable from the cold, leaden sky on silver plate landscape pictures that are mirror images on top of it all.

I shall therefore describe my process that I have no intention of keeping secret. However, I must add that the lack of detail will be suitably amended only after I have better equipment at my disposal.

We begin by breathing on a normal colourless flat window glass, cut glass for mirrors is even better, and rubbing it with a dry soft linen cloth and warming it moderately.

The light-sensitive basis is then applied by lighting a specially prepared sulphur stick the size of a match in a suitable tube and holding the plate 3 inches above it. In a very short time, the plate will be coated with a pearl white layer having a bluish red translucent character under light.

The sulphur stick is prepared by dipping a piece of the pith of a common rush into sulphur with added mastic thus imbuing it in a manner similar to matches. A piece of the ending product is then impaled on a brass needle and attached to the middle of the tube and lit.

The sulphured plate must then be lightly impregnated with iodine vapours for a few seconds. Unfortunately, I have so far been unable to use any substances that would quicken the process, but their proper usage will be the subject of later experiments.

The plate is then inserted into the prepared camera, which is now light-sensitive, and exposed for approximately one minute. During exposure, mercury atoms will rise from the iron bowl at the bottom of the instrument and subside onto the exposed places.

Experiments using a mercury box (Quecksilberkasten) have not produced any results.

When the plate is removed from the camera, it shows only faint traces of an image. Under the influence of bromine vapours, the image then instantly appears. The pictures are fixed by holding them over alcohol and by pouring it over them.

The entire process takes between 5 to 8 minutes.

The pictures could probably be made visible with silver or etched with hydrofluoric acid. The used substances are so sensitive that the aforementioned layer changes instantly under direct sunlight and after 5 minutes we get a Moser picture if the plate is inserted in a book. The attached contact picture created in this manner is easiest to discern when illuminated; in daylight, greater distance is required to look through the plate on the centre of a window or on a piece of paper that has been attached there. Letters on a yellow background appear blue because the picture was processed with bromine after contact. The second contact picture is a rosette produced using a negative on a plate that has been sulphured several times. Furthermore, you will find attached a quite successful example of a mountain landscape picture taken around Bled. The mountain's snow-covered peak is purple and the colours (hues) are soft so it is not perfect, but anything more is not possible with the limited resources that I have at my disposal. The fourth image was created in a different manner; I should probably explain in greater detail the practical value of photography on glass as well as the resources required to transfer images on paper. A plate coated in a rubber solution and impregnated with sulphuric vapour will produce a blurry positive image including all the details already in the camera. We incise the outlines of the picture with an engraving needle all the way to the glass. Afterwards, we rub printing ink onto the plate and thus fill the incised outlines and after that we remove and wash away the soluble layer of rubber and the printing ink on it by pouring water on the plate (the ink remains only on the outlines). The picture is transferred on paper by placing the paper on the plate and stroking it with a polishing tool. I shall discuss my other process-the invention enabling prints to be made from elastic plates without using presses or printing ink on glass, paper or any other material of your choosing-on some other occasion. As the invention is still in the development stage, it would be unfair to expect perfect results. We can, however, expect to achieve significant progress by using any of a number of substances that have yet to be tested, especially carbon sulphide and potassium chlorate. But what is needed most is a bigger Voigtländer device with a high light intensity if we want the darker parts of the pictures to be discernible as well. However, the purchase of this device is not very likely in my current circumstances."

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January 19