Photographic Plates

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Plates, Photographic


photosensitive materials in the form of sheets of glass coated with an emulsion of silver-halide microcrystals uniformly distributed in gelatin. The glass must be colorless, smooth, and without visible defects. Photographic plates are made in various standard sizes, ranging from 4.5 × 6 to 50 × 60 cm.

Photographic plates are classified as either general purpose or special purpose, depending on their photographic properties. General-purpose plates are used for artistic and documentary photography and for various scientific and technical purposes. Plates of this type that are manufactured in the USSR have varying degrees of light sensitivity (from 22 to 350 GOST [State Standard] units), color sensitivity (orthochromatic, panchromatic, and isopanchromatic), and contrast (normal, high-contrast, and low-contrast).

Special-purpose plates are intended for scientific and technical use and fall into the following subgroups: (1) diapositive—non-sensitized, low-sensitivity, and high-contrast; (2) reproduction— high-contrast; (3) micro (for photomicrography)—high-definition orthochromatic; (4) astronomical—high-sensitivity and high-contrast; (5) spectral UV—with increased sensitivity to violet and ultraviolet rays; (6) infrachromatic—sensitive to infrared rays; and (7) phototheodolite—orthochromatic, high-contrast, high-definition, and high-resolution.

All photographic plates are packaged in cardboard boxes with opaque packing. General-purpose plates are processed with general-purpose developers, but most special-purpose plates require special developers. A photographic plate’s emulsion swells in water and photographic solutions and can melt at 37° -40°C. For this reason, the use of photographic plates at higher temperatures is not recommended.


Kraush, L. Ia. Fotograficheskie materialy. Moscow, 1971.


References in periodicals archive ?
He would have had to mix the chemicals for the photographic plates, apply them to the glass plates, and then take the photograph before the chemicals had dried.
Where the density of the tissue blocks X-rays, for example with bone, the photographic plate shows up white.
Although digitization might soon make photographic plate technology obsolete, the detailed information on the plates won't go stale.
Rather than laboriously photographing small patches of the night sky at a variety of wavelengths, MacGillivray relies on a computer and two huge archives of photographic plates taken at red and blue wavelengths.
Although most of Slipher's experiments with photography did little to improve the quality of his early planetary pictures, his methodical experimentation in 1918 led to the standardization of photographic plates for astronomical photometry, which were used until the advent of digital photography.
Anna Draper had worked closely with her husband, recording observations, mixing chemicals, and preparing photographic plates.
Using the StarScan plate-measuring machine, he had to determine the exact positions of the many thousands of stars recorded on photographic plates sent from Flagstaff.
The orderly rows of atoms within the crystal deflect these X-rays in particular directions to produce a distinctive pattern of spots on a photographic plate.
Thus, the measured brightness of a quasar image on a photographic plate might not reflect the true brightness of the object.
Many researchers are now beginning to think of a crystal as simply any solid that yields a diffraction pattern consisting largely of well-defined, bright spots, as recorded on a photographic plate when X-rays or electrons pass through the material.
Several pages of inset black-and-white photographic plates illustrates this captivating, expertly researched, and thoroughly immersive saga.
The search bore fruit thanks to records from the Digital Access to a Sky Century at Harvard (DASCH) project, a digital collection of roughly 500,000 photographic plates taken by Harvard astronomers between 1885 and 1993 (S&T: May 2015, p.

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