Gamma

gamma

The way brightness is distributed across the intensity spectrum by a monitor, printer or scanner. Depending on the device, the gamma may have a significant effect on the way colors are perceived. Gamma is technically the relationship between the input voltage and resulting intensity of the output. A perfect linear device would have a gamma of 1.0 and be plotted on a graph called a "tone curve" as a straight line. Although a scanner is fairly linear, the tone curve of a monitor or printer is bent, yielding a gamma in the range of 1.8 to 2.6, which effects midrange tones. See gamma correction.

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gamma

1. the third letter in the Greek alphabet (Γ, γ), a consonant, transliterated as g. When double, it is transcribed and pronounced as ng

2. the third highest grade or mark, as in an examination

3. a unit of magnetic field strength equal to 10^--5 oersted. 1 gamma is equivalent to 0.795 775 × 10^--3 ampere per metre

4. Photog Television the numerical value of the slope of the characteristic curve of a photographic emulsion or television camera; a measure of the contrast reproduced in a photographic or television image

5. 

a. involving or relating to photons of very high energy

b. relating to one of two or more allotropes or crystal structures of a solid

c. relating to one of two or more isomeric forms of a chemical compound, esp one in which a group is attached to the carbon atom next but one to the atom to which the principal group is attached

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gamma [′gam·ə]

(chemistry)

The gamma position (the third carbon atom in an aliphatic carbon chain) on a chemical compound.

(electromagnetism)

A unit of magnetic field strength, equal to 10 microoersteds, or 0.00001 oersted.

(graphic arts)

A numerical indication of the degree of contrast in a television or photographic image; equal to the slope of the straight-line portion of the H and D curve for the emulsion or screen.

(mechanics)

A unit of mass equal to 10^-6gram or 10^-9kilogram.

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(language)

GAMMA - 1. A language for matrices and generation of mathematical programming reports. ["GAMMA 3.3 for MPS/MPSX, IBM System:/360", Bonnor & Moore Assocs (Mar 1975)]. 2. A high-level parallel language. [Research Directions in High-Level Parallel Languages, LeMetayer ed, Springer 1992].

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Gamma 

(1) A conventional unit that is sometimes used for measurements of small masses: 1 gamma = 10^-6 g. The designation “microgram” (μg) is more frequently used than “gamma.”

(2) The name of a hundred-thousandth part of an oersted (the unit of magnetic field strength in the cgs system of units) that is used mainly for measurements of terrestrial magnetism and cosmic magnetic fields. It is designated by y.

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Gamma 

the quantitative characteristic of the ability of photographic material to transmit the difference in exposure H of various parts of a photographic image by the difference in the optical density D of the parts. The gamma is equal to the tangent of the angle of inclination to the axis log H of the straight portion of the performance curve of the material (provided that the scales of the axes log H and D are identical). Other conditions being equal, the gamma characterizes the uniformity of the silver halide crystals of the photographic emulsion with respect to light sensitivity. As a rule, it is greater for low-sensitivity positive materials and less for high-sensitivity negative materials. The gamma is one of the most important sensitometric parameters of a photographic material.