DE261342C - - Google Patents

Description

IMPERIAL

Iv PATENT OFFICE.

PATENT LETTERING

CLASS 57b. GROUP

in CHICAGO.

Patented in the German Empire on May 10, 1910.

The piatinotype paper owes its popularity mainly to the color of the paper on it manufactured images. With regard to the high price of platinum, attempts have been made to to replace the same with cheaper metals. For this purpose, photographic papers were used suggested a sensitive layer of ferric oxide and a silver salt, but that silver picture made from it possesses in the

ίο usually a reddish or reddish brown color. There were also papers with a sensitive layer of ferric oxide and a Mercury salt has been proposed, but the inventors found that it is so obtained In contrast, mercury image is not stable

to the information in Eder's Handbuch der Photographic II. ed., 4th vol. ₁ , pp. 304 and 305.

Experiments related to the present invention

led, showed that a permanent silver image, which is characterized by a dark color similar to that obtained with piatinotype paper, Can be obtained when a small amount of a mercury salt is combined with a silver salt and ferrioxalate is used. In the picture obtained is no mercury found; the mercury salt seems to only influence the color tone of the picture, that of the pure silver picture would be reddish in color.

According to the present invention, the photosensitive layer contains a small amount of a mercury compound in addition to ferric oxalate and a silver compound. The development 35

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Winding is done in a similar way to that with ordinary platinotype papers.

The production of the new copy paper is advantageous as follows. One solves in 75 parts by weight of water 12 parts by weight of ferrioxalate, 5 parts by weight of silver nitrate, 1.2 parts by weight Mercury citrate, 1 part by weight of oxalic acid, in this order one after the other.

Instead of the applied 5 parts of silver nitrate and 1.2 parts of mercury citrate Appropriate amounts of other silver or mercury compounds are used. Here note that one z. B. can take mercury oxide, which is in the iron oxalate solution dissolves quickly; on the other hand, silver oxide is and can be sparingly soluble in this solution therefore only to a certain extent the silver nitrate or another easily soluble silver salt substitute.

The ratio of silver to mercury in the silver and mercury compounds used is approximately in the above example using 12 parts of ferric oxalate 3.5: 0.46, whereby the mercury content can be changed.

If you reduce the content, you get reddish or brownish black tones, and if you increase the content, bluish black tones.

By adding potassium oxalate or stannic citrate or other salts, the amount

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of the applied mercury salt without any

Reduced penalties for the new beneficial effect will; z. B. if 5 parts of potassium oxalate are added to the solution, can 'der Mercury content reduced to 0.2 parts.

If 1 to 3 drops of an io percent Solution of potassium dichromate too. 31 g each of the Solution, which is prepared in the manner described above, are added, so the impregnated paper gives high-contrast prints.

After all the solid ingredients have been dissolved in water, the liquid will rise the paper coated and dried. This seemed in the same way as now commercially available Piatinotype papers. The paper will be dry and against as usual Store away from light and moisture until use.

As stated above, a change in the mercury content causes a corresponding one Change in the color of the image. In the example given above, e.g. B. the mercury oxide can be increased to about 0.5 g per 31 g of solution.

The paper at hand is copied until the image appears faint. It will then in a developer solution of neutral potassium oxalate bathed, which z. B. consists of 1 part of potassium oxalate to 4 parts of water. When the image is developed it is cleared up by placing it in a bath which is on ι part of hydrochloric acid contains 64 parts of water. In place of hydrochloric acid there are also other acids usable e.g. B. citric acid, nitric acid or sulfuric acid. One proceeds appropriately so that you change this bath three times by taking the picture in the first bath for 5 minutes, then, after the used liquid has been poured off or drawn off, in a second bath for 10 minutes and finally in the third bath Left for 15 minutes. It is then washed in running water for 15 minutes.

The copy will now be in 10 minutes A fixer of sodium hyposulnt is placed, which consists of 1 part of hyposulfite to 20 parts Water, and immediately washed properly.

According to the present invention, sodium or potassium phosphate can be added to the potassium oxalate developer in amounts ranging from 10 to 35 percent by weight of the potassium oxalate applied to fluctuate, to be added. At times, a soluble tartrate can also be used, especially Sodium tartrate. The two additives, namely of phosphate and of tartrate, are said to increase the intensity of the increase the black areas contained in the final image, just like when developing Platinotype paper.

Instead of using hydrochloric acid to clear the picture, you can also use it in a Dip the solution consisting of 1 part sodium hyposulphite, ι part sodium metabisulphite or sodium pyrosulphite and 100 parts of water. Here, too, the procedure is the same as for the hydrochloric acid bath expediently so that one uses fresh solutions three times, so that the image in the first bath for a short time, e.g. B. 5 minutes 70 long, 10 minutes in the second bath and 15 minutes in the third bath. It is then washed in running water for 15 minutes.

The image produced in this way is completely permanent and contains, as far as determined by analysis has been, no trace of mercury. It is assumed, as I said, that the mercury has a catalytic effect on the others Substances acts and is completely removed even in the course of development. The finished copy is the best if it is made with the paper at hand Platinotype paper completely equivalent and stronger in its deepest color tones.

Otherwise it cannot be distinguished from that, except by chemical analysis, and is much cheaper to manufacture.

Claims (3)

Patent-to sayings: 1. Photographic paper, its delicate Layer containing iron oxalate and a silver salt, characterized in that it contains a small amount of a mercury compound is added to the preparation. 2. A photographic paper according to claim i, characterized in that silver and mercury salts are present in the ratio of about 3.5 parts of silver (Ag) and about 0.46 parts of mercury (Hg) to about 12 parts of iron oxalate. 3. A photographic paper according to claim ι or 2, characterized in that with a reduction in the mercury content, potassium oxalate or tin citric acid is added to the preparation.