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TECHNOLOGY OF DRAWING OF HALF-TONIC IMAGES
ON METAL SURFACE

A collection of methods for the manufacture of technology secrets for all occasions

Glossary

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Image acquisition on a metallic surface is based on the properties of chromium-plated colloids to be hardened under the action of light. The tool described below allows you to get line images .

A well-polished or evenly matted metal plate is degreased in hot soapy water, washed under running water and also dried.

On the dried plate pour a small number of the solution, consisting of the following components:
1) Wood glue (cleaned) - 30 grams ;
2) Egg white (whipped into foam) - 15 gr ;
3) Ammonium bichromate - 2.5 g ;
4) Mass ammonia - 3: 4 drops ;
5) Water - 100 ml.

Ammonium bichromate is ground in a porcelain mortar and dissolved separately in 50 ml of water. To the rest of the water elements add protein, but then glue. Both solutions are mixed. The mixture is allowed to stand for 10-12 hours , after which it is filtered through cotton wool. The solution retains its properties for three to four days.

Joiner's glue is cleaned using the following method: 25 g of joinery is also mixed with 25 g of glue, pouring 50 ml of water into the mixture, leaving it to swell. Then the mash is melted in a water bath, egg white (half an egg) is added, and the mixture is thoroughly mixed and boiled for 10 minutes . Into the hot solution pour 0.1 g of chrome alum powder, stir the solution and pour into a narrow cylindrical vessel (beaker). After some time, the protein, but with it also all the impurities will settle to the bottom. After the mash is mashed, the walls of the vessel are slightly warmed up, and the mass easily falls out of the inverted vessel. Higher and lower layers of the mass are cut off with a knife, but the remaining purified glue is used to prepare the solution.

Having poured the solution onto a metal plate, they allow it to spread evenly over the entire surface, for which they tilt the plate in different directions, or roll it with a rubber roller. The excess solution is poured from the corner of the plate back into the flask. The plate is placed vertically for drying (in a darkened room).

Next, prepare the desired image in any graphics program such as Corel Draw, Adobe Photoshop , etc. Then we translate it into negative (for example, in Adobe Photoshop - menu Image / Settings - Invert .

We print on a jet (laser) printer image in a mirror on a transparent film. We set the highest print resolution. The optimal variation for a photo image is 2400 * 1200 dpi , for graphics - 1440 * 720 dpi , for diagrams, text, and stroke information - 720 * 720 dpi .

On the dried plate impose a dashed negative, put it in the copy frame also exhibit in bright light. Exposure determined by experienced route.

The exposed plate is immersed in a cuvette with room temperature water, shaking the cuvette, it is shown for about 1 minute . After that, the plate is slightly rinsed under a weak stream of water and also immersed in a 1% aqueous solution of aniline dye, in which place the invisible until this image is painted is also made visible. The color of the image will depend on the color of the dye (for example, if you add a scarlet dye, then the tones of the image will be reddish). After staining, the plate is well washed in running water and also dried.

another means is that the exposed plate is rolled with a rubber roller, coated with a thin layer of finely ground lithographic paint, later developed in water, washed, dried and also varnished with some kind of transparent varnish.