contrast

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Related to positive contrast: negative contrast

contrast

1. (in painting) the effect of the juxtaposition of different colours, tones, etc.
2. 
a. (of a photographic emulsion) the degree of density measured against exposure used
b. the extent to which adjacent areas of an optical image, esp on a television screen or in a photographic negative or print, differ in brightness
3. Psychol the phenomenon that when two different but related stimuli are presented close together in space and/or time they are perceived as being more different than they really are

Contrast

A juxtaposition of dissimilar elements to show the differences of form or color, or to set in opposition in order to emphasize the differences.

Contrast

 

in psychology, the subjective exaggeration of the differences between perceived objects or between certain sectors of the visual field during their spatial (simultaneous contrast) or temporal (successive contrast) contiguity. Thus, when the color black is placed next to white it seems even blacker. Contrast may also be manifested in color change. For example, a gray square on a red background seems greenish blue; on a blue background it looks orange. The sharpest contrast of two colors is expressed at the boundary of the two areas (boundary contrast). The phenomenon of assimilation is the opposite of contrast. Contrast is widely used in various forms of art and literature.

REFERENCES

Vudvorts, R. Eksperimental’naia psikhologiia. Moscow, 1950.
Teplov, B. M. “Vzaimodeistvie odnovremennykh svetovykh oschchushchenii.” In Zritel’nye oshchushcheniia i vospriiatiia. Moscow-Leningrad, 1935.

contrast

[′kän‚trast]
(communications)
The degree of difference in tone between the lightest and darkest areas in a television or facsimile picture.
(computer science)
In optical character recognition, the difference in color, reflectance, or shading between two areas of a surface, for example,a character and its background.

contrast

The white level of a display screen. The contrast adjusts how bright the white is. See brightness and contrast ratio.
References in periodicals archive ?
In the third experiment of the same study, free operant responding in college students was studied under mult schedules, examining positive contrast with half the subjects and negative contrast with the other half.
Thus, if positive contrast occurs, a situation is observed wherein a participant is responding faster, but not earning more reinforcers.
positive contrast would be demonstrated by data points above this line).
Four pigeons served as subjects in the positive contrast condition.
Each pigeon in the positive contrast condition experienced this schedule series twice.
The negative contrast condition was identical to the positive contrast condition with the exception of the schedules used.
They present the percentage change in the number of draws from the second container in the positive contrast condition from the median number of draws from the second container in the baseline conditions for each subject.
Conditions 4 through 6 were analogous to the positive contrast procedure in Experiment 1.
Figure 4 shows that positive contrast was also observed.
Positive contrast was obtained in the first two upshifts only.
Positive contrast was expected with deprived animals over initial shifts but was not expected to recur once control animals reached high levels of responding on later days, thus producing a ceiling effect.
Positive contrast did not occur with nondeprived subjects, who failed to reach the levels of the 32N control group on several upshift days.