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The use of high pure aluminum

The use of high pure aluminum

The combination of physical, mechanical and chemical properties high pure aluminum determines its wide use practically in all fields of technology, especially in the form of its alloys with other metals.

High pure aluminum obtaining

High pure aluminum obtaining

High pure aluminum can be obtained in three ways: by zone-melting, distillation through subgalogenidy and electrolysis. Of these methods of producing high pure aluminum, industrial utilization was a way to zone melting.

The principle of zone melting is in multiple passage of the molten zone along the ingot of aluminum.

It is necessary to prepare aluminum intended for zone melting, preparation consists in filtering, degassing and etching. Filtering is necessary for removal infusible and solid oxide pellicle, dispersed in the metal, from aluminum.

Aluminum

Aluminum

Aluminum is Chemical element of group III of Periodic table, atomic number is 13, atomic weight is 26, 98154. Silvery-white metal, lightweight, compressible, highly conductive, melting temperature = 660 ° C

The treatment of black-white photographic paper (a few tips)

The treatment of black-white photographic paper (a few tips)

A box with a black-white photo paper can be opened only in photo room in the dim light of a safe and comply with the conditions required until the end of fixation.

During the session, your hands should be clear, because you can leave indelible stains on it. Use gloves when handling chemical black-white photo paper.

Just a couple of tips: take a sheet of black - white photographic paper only  in unexposed region, and if there will be spots, the edges can always be cut off without any damage.

Storing of black-white photo paper

Storing of black-white photo paper

The main reason that it is not necessary to store too much paper is its fragility. If not stored properly, black-white photo paper can deteriorate very quickly - in a matter of months.

However, with black- white photo paper «Slavich» this does not happen. We still get letters which say that people find a black-white photo paper «Slavich», since the release of which has been more than 30 years and which has turned out excellent print black-white photos!

Black-white photographic: Conventional or multi-contrast?

Black-white photographic: Conventional or multi-contrast?

Another fundamental difference between the grades of black-white photographic papers is the desired method for adjusting the contrast while printing.

Plain black-white photo paper has a certain degree of contrast, ranges from 0 to V. Graduation II is considered "normal" and is suitable for all normal cases. As the number increases the contrast is increases too, so 0-degree contrasts black-white photographic papers are "soft", IV or V degrees are "contrast".

Choice of black and white photographic paper

Choice of black and white photographic paper

There are a lot of different types of photo paper for black-white printing. Each of them has its own unique characteristics, but it is first necessary to make a choice between black-white photo paper on plastic base (RC) and on barytic base (FB).

Light sensitivity of photographic paper

Light sensitivity of photographic paper

At the heart of obtaining the photographic image physical properties and chemical action of light lie. Physical properties of light allow to receive by means of the camera on a plane surface the optical (luminous) pattern of subjects surrounding us, and chemical action — to imprint this image on photographic materials (photoplates, a film, photographic paper).

The surface layer of photographic materials consists of the substances changing under the influence of light. Such substances are called light sensitive.

Silver halide

Silver halide

Unique ability of silver halide to form the latent photographic image which is capable to amplify by 107 – 1010 times by action of special organic regenerates in case of a photolysis does silver halide irreplaceable for record of optical information.  Despite of intensive development of electronic means of optical information record of the silver halide photography remains a classical method of obtaining visual images in hard copies.

Magic of the black-and-white photography

Magic of the black-and-white photography

Using a black-and-white method of the photography, it is possible to cause feeling of mystery and nostalgia in the contemplator, darkening any sections or selecting them. As, the black-and-white photo has today a number of advantages before the color photo. For example, it is difficult to correct unsuccessful shades of the color photo, in the black-and-white photo in it most often there is no need. As in the black-and-white photo shades are smoothed, any defects on object of the photo become in black-and-white execution by less perceptible.