SMPTE RP 166-1995 Critical Viewing Conditions for Evaluation of Color Television Pictures.pdf

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1、SMPTE RPULbb 95 8357401 O002008 b48 = SMPTE RECOMMENDED PRACTICE Critical Viewing Conditions for Evaluation of Color Television Pictures RP 166-1995 1 Scope 1.1 This practice specifies the environmental and surround conditions that are required in tele- vision or video program review areas for the c

2、onsistent and critical evaluation of 525-line, 59.94-field television signals and other video program material at different technical facilities on properly aligned color picture monitors. 1.2 This practice also is designed to provide for repeatable color grading or correction and the rendering of s

3、ubjective assessments when used with RP 167. 2 Color monitor characteristics Parameters for the monitor screen at reference white (100 IRE) are as follows: - a chromaticity of illuminant Da; - a screen aim luminance of 120 cci/m2 (35 fL). 3 Observer viewing characteristics 3.1 The observer should ha

4、ve normal color per- ception. 3.2 Adequate time must be allowed for visual adaptation to the viewing environment. 3.3 The observers distance from the monitor screen should be 4-6 picture heights. 3.4 The observer should view the monitor screen at a preferred angle in both the horizontal and vertical

5、 planes of O“ * 5“, but no greater than 2 15“, from the perpendicular to the midpoint of the screen . Page 1 o 4 pages 4 General conditions - Viewing area decor 4.1 The viewing area decor should have a generally neutral matte impression, without dominant colors (see A.4). It is most critical that ar

6、eas in the field of view be devoid of vivid colors. 4.2 Surface reflectances should be nonspecular and should not exceed 10% of the peak lumi- nance value of the monitor white. Surfaces which may be visible in the monitor screens, due to the mirror effect, should have a nonspecular surface reflectan

7、ce of less than 15%. 4.3 Production desk and control console sur- faces should have a generally neutral matte finish without dominant colors or specular features. 5 Surround characteristics 5.1 The surround wall should be either illumi- nated or reflective (see A.2 and A.3). 5.2 The reflective surro

8、und should be a visually neutral surface (preferably white or gray). 5.3 The reflective surround should be illurni- nated with a light quality closely matching illumi- nant D65. Ganerally, the reflective surround receives its illumination from the controlled am- bient lighting in the room (see claus

9、e 7). , 5.4 The reflected light from the surround or background in the field of view should have a peak luminance of 12 cd/m2 (3.5 fL) which is nominally 10% of the monitor screenls) refer- ence white (see A.2). Practice has shown that a Copyright O 1995 by the SOCIETY OF MOTION PICTURE AND TELEVISI

10、ON ENGINEERS 595 W. Hartsdale Ave., White Plains, NY 10607 Approved May 11,1995 (914) 761-1100 SMPTE RP*Lbb 95 H 8357403 O002009 584 W RP 1-19% uniform field is not optimum but that a gradation of intensity from top to bottom, or bottom to top, is more pleasing. 5.5 The surround should have an area,

11、 outside the monitor screen mask, of ideally at least eight times the monitor screen area (see figure 1). 5.6 If two monitor screens are mounted in one monitoring wall, then the total surround area should ideally be five times the total monitor screen area (see figure 2). 5.7 For monitors mounted in

12、 studio control room walls, see annex B. 6 Acceptable methods 6.1 A good practical approach is to have a monitor placed in a free-standing environment 2.5 to 5 screen heights in front of a wall provid- ing the visual surround. The surround receives its illumination from directly controlled and am- b

13、ient lighting in the room (see A.5). 6.2 Another approach is to mount the monitor in a wall with its face approximately flush with the surface of the wall. 7 Viewing room lighting characteristics (see annex C) 7.1 All light sources in use during picture as- sessment or adjustment should have a color

14、 quality closely matching the monitor screen at reference white; i.e., D65 (see A.5). 7.2 The ambient light reflected from the screen of a switched-off monitor should be the lowest possible level (see A.6). 7.3 Reflections on the monitor screen should not cause a perceptible impairment from the norm

15、al viewing position (see A.7). 7.4 The production desk and control consoles where a script is read should be illuminated to a light level of about 100 Ix (10 fc). The illumina- tion on the general working surfaces of the production desks and consoles should be 30-40 Ix (3-4 fc) (see annexes A.8 and

16、C). Figure 1 - Single monitor surround area Figure 2 - Two-monitor surround area SMPTE RP*1bb 95 m 8357401 O002010 2Tb RP 186-1995 Annex A (informative) Additional data A.l Reference white Reference white is obtained when a color video signal at a specified luminance level with zero color subcarrier

17、 is displayed on a properly aligned color picture monitor. A.2 Surround The surround is defined as the light, visible to the observer, from a plane or from behind a plane coincident with and surrounding but not including the viewing screen). A.3 Characteristics of surrounds - Chromaticity and lumina

18、nce A surround, lit either from behind or from the front, makes picture matching easier to control. The surround, rather than the base luminance, becomes a fixed neutral visual refer- ence. The surround will appear gray (neutral) compared to monitor screen) since it is about 10% of the light intensi

19、ty of the monitor screen( reference white and the same color quality. The surround stabilizes the eye to achieve adapta- tion because it provides the observer) with a fixed neutral visual reference for color and brightness judgements, in- creases the apparent picture contrast, and provides for a mor

20、e pleasant and less fatiguing work environment. A.4 Decor The viewing room should provide a pleasant environment. Areas in the field of view at normal operating positions should be a neutral surface color. For other areas, the use of pastel colors is preferred if a. change from neutral is desired. T

21、he Munsell color system defines acceptable color choices by a category called “nearly neutral.“ (See ASTM D1535-89.) A.5 Viewing room light source The preferred luminaires are daylight-type fluorescent lights. Their light output can be controlled over a large range without changing the color of ligh

22、t (see note 1 of A.8). Annex B (informative) Studio control room monitor walls It is offen necessary to have black-and-white monitors sur- rounding one or more color monitors in a studio control room environment. These black-and-white monitors should be the same color temperature as the properly adj

23、usted color moni- tor), 6500 K. Black-and-white monitors are normally equipped with P4 phosphors, about 9300 K. This cooler color temperature prevents the background surrounding the color monitors from remaining neutral, 6500 K. Monitors with CRTs contain- ing P4 phosphors should have their CRTs cha

24、nged to D65. Most manufacturers provide a CRT with 6500 K phosphors Incandescent light sources filtered to daylight color tem- perature are also acceptable. Caution should be exercised in the use of this type of lighting in that most incandescent sources significantly change color when dimmed by con

25、trol- ling source voltage. A.6 impact of light For a tutorial on the impact of light on the screen, see “Operations Adjustment of Picture Monitors in Television Studios,“ by C. A. Siocos, J. SMPTE, 74: 11 -1 4, January 1965. A7 Veiling reflection A veiling reflection is defined as a regular reflecti

26、on which is superimposed upon diffuse reflections from an object and which partially or totally obscures the details to be seen (on the color monitor screen) by reducing the contrast. 118 illumination A fluorescent script luminaire without a special louver, mounted about 122 cm (48 in) above a surfa

27、ce will create a light level of about 500 Ix (50 fc) on the surface. When a special matte-black egg-crate louver is installed, the lighting level is reduced to 1 O0 Ix (1 O fc) and the angle of light spread is less than 15“. It is normal to have the illuminated area cut off within 50 mm (2 in) at th

28、e edge of the work surface. For additional fixed light intensity control, neutral density filter material can be installed on the upper surface of the special louver to achieve the correct illumination levels. NOTES 1 A fluorescent compatible dimmer should be used to avoid flicker. 2 Fluorescent lum

29、inaires can provide no hard edge of light cutoff; therefore, the control area should be configured within this constraint. as an option in black-and-white monitors. When used, the peak-light output of these black-and-white monitors should be lower in value than that of the color monitors, usually tw

30、o-thirds of the color monitor peak white value. It is offen important that the color monitor(s) be the primary viewing object in a wall full of monitors. The light output intensity of surrounding black-and-white monitors can divert attention from the color monitor(s) if the black-and-white monitors

31、are set equal to or above the color monitor(s) intensity. Page 3 of 4 pages SMPTE RP*Lbb 95 8357403 0002OLl 132 RP l&lssS Annex C (informative) Surround specifications C.l Background C.2 Illuminant The monitor is set in front of or into a wall. If in front of a wall, the tube face is typically 2.5 t

32、o 5 picture heights from the wall. The color of the monitor wall and the side walls within the field of view should be neutral. The illuminant should approximate DS5. (Distance to wall: 2.53 screen heights if not “in-wall”) -7- Operator-to-screen distance: 4 to 6 screen heights Maximum viewing angle

33、: * 15” from perpendicular to screen center T Client area: 20-100 Ix White point: 120 d/m2 DCS Maximum reflected light o should not exceed 10% of peak luminance value of the monitor white. The light falling on the unlit monitor screen face should be uniform and as low as possible. Annex D (informative) Bibliography SMPTE RP 167-1995, Alignment of NTSC Color Picture Monitors ASTM D1535-89, Standard Test Method for Specifying Color by the Munsell System