1、1 Scope1.1 SpecificationsThis standard specifies a method for the determina-tion of speed of 16-mm, 8-mm type R, and 8-mm typeS reversal color camera films intended for direct pro-jection in motion-picture photography.1.2 Basic standardISO 2240 constitutes the basis for this standard.2 Normative ref
2、erencesThe following standards contain provisions which,through reference in this text, constitute provisions ofthis standard. At the time of publication, the editionsindicated were valid. All standards are subject torevision, and parties to agreements based on thisstandard are encouraged to investi
3、gate the possibilityof applying the most recent edition of the standardsindicated below.ANSI/PIMA IT3.301-1990 (R1997), Photography Cameras Automatic Controls of ExposureISO 2240:1994, Photography Colour ReversalCamera Films Determination of ISO Speed3 Exposure timeExposure time shall be between 1/2
4、5 and 1/50second.Annex A (informative)DensityExperience has shown that a density level selected as opti-mum for a transparency is influenced by screen luminance.A less dense transparency is selected if the screenluminance is reduced. Because of the difference in screenluminance typical of 35-mm slid
5、e projection (approximately137 candelas per square meter 40 foot-lamberts) and thattypical of 16-mm motion-picture film projection (assumed torange from approximately 48 cd/m2to 62 cd/m214 fL to 18fL), a variation in preferred picture density may lead toa desire for approximately 1/3 camera stop inc
6、rease inexposure for the latter. This difference is not consideredsufficient to warrant a change in the sensitometric testmethod for motion-picture use. However, many 8-mm pro-jection conditions are different enough in luminance from55 cd/m2(16 fL) to require lighter or darker pictures.ANSI/PIMA IT3
7、301 suggests that an adjustment which per-mits 1/3 stop more exposure for 8-mm films is permissible.This is standard practice by camera manufacturers. How-ever, since there is no standard for 8-mm projection, it is notpractical to write a separate standard for determining speedof 8-mm films.for Mot
8、ion-Picture Film 16- and 8-mm ReversalColor Camera Films Determination of SpeedRevision ofANSI/SMPTE 146M-1996SMPTE 146M-2001SMPTE STANDARDApprovedJune 6, 2001Copyright 2001 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS595 W. Hartsdale Ave., White Plains, NY 10607(914) 761-1100REAFFIRMED 2006
