Recommendations for density and contrast range of monochrome films slider and photographic opaques for television

2015 ◽  
Keyword(s):  
Contrast Range

Measurement of Comfortable Contrast Range of Stereo Image Based on Salient Region

2018 ◽  
Vol 38 (2) ◽  
pp. 0215001
Author(s):  
胡佳洁 Hu Jiajie ◽  
李素梅 Li Sumei ◽  
常永莉 Chang Yongli ◽  
朱兆琪 Zhu Zhaoqi ◽  
侯春萍 Hou Chunping
Keyword(s):  
Stereo Image ◽  
Salient Region ◽  
Contrast Range

A Study of the Effect of Standard Laboratory Processing on Speed and Resolution of Three Black and White Aerial Films

1983 ◽  
Vol 37 (1) ◽  
pp. 3-10
Author(s):  
E. A. Fleming ◽  
M. Landreville ◽  
E. Nagy
Keyword(s):  
Type A ◽  
The Other ◽  
Small Scale ◽  
High Contrast ◽  
Aerial Photo ◽  
Standard Laboratory ◽  
Average Gradient ◽  
Black And White ◽  
Contrast Range ◽  
Film Speed

Three aerial films were tested using standard aerial photo laboratory processing procedures for three different chemistries. Relationships were established with respect to average gradient, speed, base plus fog, graininess and resolution for low, medium and high contrast targets. The films compared were Kodak Double-X type 2405, Kodak Plus-X type 2402 and Kodak Panatomic-X 2412. The processing was done in a Kodak Versamat processor using Type A, 885 and Versaflo chemistry. The results indicated that processing in 885 chemistry enhanced film speed. The versatility of Double-X in terms of speed and contrast range was demonstrated, however the resolution of Panatomic-X greatly exceeded that of either of the other two films and shows promise for small scale mapping photography.

Trade-Off between Achromatic Colour and Perceived Illumination as Revealed by the Use of Pseudoscopic Inversion of Apparent Depth

Perception ◽  
1994 ◽  
Vol 23 (9) ◽  
pp. 1007-1023 ◽  
Author(s):  
Alexander Logvinenko ◽  
Galina Menshikova
Keyword(s):  
Apparent Depth ◽  
Bisection Method ◽  
Trade Off ◽  
Classical Form ◽  
Inverse Proportion ◽  
The Mean ◽  
Contrast Range

The albedo hypothesis was tested under apparent transformations of perceived illumination and achromatic colour induced by pseudoscopic inversion of apparent depth. Looking through a pseudoscope made a cone attached to a vertical white screen look like a conical hole in the screen. This in turn caused the shadow which the now ‘invisible’ cone cast on the screen to change its appearance and to look like a darkly pigmented area. The darkness of the shadow before the pseudoscopic reversal and greyness of colour afterwards were measured by means of psychophysical scales for darkness and greyness set by the bisection method. Contrast of the shaded area was varied from 0.17 to 0.96 in 7 steps, the mean illuminance of the screen having been maintained at 40 lx. Although the albedo hypothesis in its classical form was not confirmed, it was found that darkness of shadow varied linearly in inverse proportion to greyness of colour within the entire contrast range. This is in agreement with the hypothesis that achromatic colour and perceived illumination are inversely proportional to each other while the retinal illumination is constant.

Effects of Contrast on Perceived Size of Visual Patterns: Theory, Data, and Implications

1993 ◽  
Vol 37 (19) ◽  
pp. 1355-1359
Author(s):  
B. Arthur Kirkland ◽  
Elizabeth Thorpe Davis ◽  
Dean Yager ◽  
Troy Surdick
Keyword(s):  
Spatial Frequency ◽  
Dynamic Range ◽  
Detection Threshold ◽  
Night Vision ◽  
Visual Patterns ◽  
Visual Processes ◽  
Design Systems ◽  
Contrast Perception ◽  
Contrast Range ◽  
Single Set

The perceived spatial frequency of a visual pattern can vary with changes in contrast. Because size is inversely related to spatial frequency and because perceived size is an important distance cue, this has implications for task performance in a variable contrast environment. These environments are common in everyday situations, such as driving in the fog, and in the use of night vision devices. Understanding the underlying visual mechanisms of this effect would help us design systems that compensate for the effect. This understanding also could further develop models of the human low-level visual processes. However, most testing of perceived size and contrast has been done at relatively high contrast levels. This research is conducted at contrast levels near detection threshold. This range allows a more thorough testing of different models of contrast detection. We tested two versions of a multiple spatial-frequency channels model of contrast perception. One model assumes a single set of channels functioning throughout the dynamic range of contrasts used here, the other assumes two sets of channels based on the parvo and magnocellular systems. Our results support the hypothesis that there is a single set of channels at work in the contrast range tested.

On the standardization of VDT's proper and optimal contrast range

Ergonomics ◽  
1990 ◽  
Vol 33 (7) ◽  
pp. 925-932 ◽  
Author(s):  
ZUXIANG ZHU ◽  
JIANMING Wu
Keyword(s):  
Contrast Range
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