SMPTE ST 117M-2001 Motion-Picture Film Photographic Audio Record Spectral Diffuse Density.pdf

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1、1 ScopeThis standard supplements ISO 5-2 and ISO 5-3 byspecifying spectral conditions suitable for determiningthe sensitometric characteristics of photographicaudio records on three-component subtractive colorfilms having records made up of dye images plussilver or a metallic salt. It does not apply

2、 to the densitymeasurement of records composed of dyes only. Theconditions of this standard are applicable to systemsof audio reproduction using the S-1 photosurface. It isrecognized that there are other types of photosurfacesused for photographic audio reproduction that do notfall within the scope

3、of this standard. This standarddefines a practical condition by means of which it isexpected that most density measurements will bemade.2 Normative referencesThe following standards contain provisions which,through reference in this text, constitute provisions ofthis standard. At the time of publica

4、tion, the editionsindicated were valid. All standards are subject torevision, and parties to agreements based on thisstandard are encouraged to investigate the possibilityof applying the most recent edition of the standardsindicated below.ISO 5-2:2001, Photography Density Measure-ments Part 2: Geome

5、tric Conditions for Transmis-sion DensityISO 5-3:1995, Photography Density Measure-ments Part 3: Spectral Conditions3 Terminology used in the densitometryof photographic color audio records3.1 Peak responseThe peak response of a densitometer is the wave-length to which the densitometer has the great

6、estresponse, including such factors as the spectral emis-sion of the light source, the combined spectral trans-mission of all optical filters in the light path, and thespectral sensitivity of the photo-sensitive receptor.3.2 BandwidthThe bandwidth of a densitometer is the range ofwavelengths to whic

7、h the densitometer is sensitive. Ina practical densitometer, this range of wavelengths isnot sharply defined; but, for the purposes of thisstandard, the bandwidth shall be considered to liebetween those wavelengths that excite, in the photo-sensitive receptor, one half the current which is ex-cited

8、at the wavelength of peak response. Theselimiting wavelengths are to be measured or computedusing the light source, all operating optical filters, andthe photo-sensitive receptor of the densitometer.3.3 Overall responseThe overall response of a densitometer is the inte-grated response of the densito

9、meter to all wave-lengths, including such factors as the spectralemission of the light source, the combined spectraltransmission of all optical filters in the light path, andthe spectral sensitivity of the photo-sensitive receptor.for Motion-Picture Film Photographic Audio Record Spectral Diffuse De

10、nsityRevision ofANSI/SMPTE 117M-1996SMPTE 117M-2001SMPTE STANDARDPage 1 of 2 pagesApprovedJune 6, 2001Copyright 2001 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS595 W. Hartsdale Ave., White Plains, NY 10607(914) 761-11004 Spectral density of photographic audiorecord on three-component s

11、ubtractivecolor filmsSpectral diffuse density of photographic audio recordon three-component subtractive color films is diffusetransmission density as measured with an instrumenthaving a response of 20-nm bandwidth peaking at 800nm 5 nm, with at least 80% of the overall responseof the instrument fal

12、ling within the 20-nm bandwidth.Annex A (informative)Additional dataIn three-component subtractive color films, dyes or colorcouplers are used to form the photographic image. Thesecolor materials are designed primarily for the visual region,but audio-record reproduction via the S-1 photosurfacesuses

13、 the infrared region of approximately 700 nm to 900 nm,which is far enough away from the visual region so that thecolor materials cannot be used efficiently, but close enoughso that they produce a measurable effect. The spectralcharacteristics of this effect depend on the type of light-absorbing mat

14、erial used for the audio record, and on themanner in which the audio record is processed. Therefore,in order to obtain uniformity of audio record densitometryamong different films and density-measuring instruments, itis necessary to specify the spectral conditions under whichthese density measurements are made. It is the aim of thisstandard to define these conditions sufficiently to ensurereasonable uniformity of density measurements, yet notso rigidly as to make impractical the obtaining of suchmeasurements.SMPTE 117M-2001Page 2 of 2 pages