1、BRITISH STANDARD BS 5550-2.12.1: 1993 Cinematography Part 2: 16 mm film Section 2.12 Miscellaneous Subsection 2.12.1 Specification for test film for assessing the picture performance of16mm motion-picture projectors UDC 778.57:778.55BS5550-2.12.1:1993 This British Standard, having been prepared unde
2、r the directionof the Cinematography and Photography Standards PolicyCommittee, was publishedunder the authority ofthe Standards Board and comesinto effect on 15September1993 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CPM/7 Draft for comment 92/
3、41135 DC ISBN 0 580 22190 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Cinematography and Photography Standards Policy Committee (CPM/-) to Technical Committee CPM/7, upon which the following bodies were represented: Association of
4、Independent Cinemas British Broadcasting Corporation British Film Institute British Gear Association British Kinematograph, Sound and Television Society British Photographic Association Broadcasting Entertainment Cinematograph and Theatre Union Cinematograph Exhibitors Association of Great Britain a
5、nd Ireland Department of Education and Science Independent Television Companies Association Institute of Amateur Cinematographers Institution of Incorporated Executive Engineers Lighting Industry Federation Ltd. National Council for Educational Technology Amendments issued since publication Amd. No.
6、 Date CommentsBS5550-2.12.1:1993 BSI 10-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 References 1 3 General 1 4 Frame dimensions and positioning 1 5 Test pattern 2 6 Components of the test pattern 2 Annex A (informative) Guidance on the use of the 16 mm moti
7、on-picture test film 4 Figure 1 Accuracy of the position of the frame of the image on the test film 2 Figure 2 Appearance of the frame on the test film 3 Table 1 Reference position and tolerances on positions of successive images 1 List of references Inside back coverBS5550-2.12.1:1993 ii BSI 10-199
8、9 Foreword This Subsection of BS5550 has been prepared under the direction of the Cinematography and Photography Standards Policy Committee. It supersedes part of the content of BS1488:1971, which is withdrawn. The content of BS1488:1971 which is not contained in this revision relates to sound test
9、films, the requirements for which are specified in BS5550-5.4.2:1983 and BS5550-5.4.5:1987. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not
10、 of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will b
11、e indicated in the amendment table on the inside front cover.BS5550-2.12.1:1993 BSI 10-1999 1 1 Scope This British Standard specifies a test film for assessing the picture performance of16mm motion picture projectors. The aspects of picture performance covered are resolution, overall focus, ghosting
12、, flare, alignment and steadiness. 2 References 2.1 Normative references This Subsection of BS5550 incorporates, by reference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the in
13、side back cover. Subsequent amendments to, or revisions of, any of these publications apply to this Subsection of BS5550 only when incorporated in it by updating or revision. 2.2 Informative references This Subsection of BS5550 refers to other publications that provide information or guidance. Editi
14、ons of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 General 1) 3.1 The film stock used for the manufacture of the test film shall be colour film the dimensions of which shall conform to BS
15、5550 -2.1.1:1984 and on which the sprocket-hole pitch shall be7.620mm 0.010mm (0.3000 in 0.0004in). NOTEPolyester film base is dimensionally more stable than acetate materials and will therefore have a longer life as a test film. 3.2 The completed test film shall be a camera-original and shall have
16、the preferredemulsion orientation specified in BS5550-2.7.1:1986; that is, emulsion towards theprojection lens. 3.3 The completed test film, including leader and trailer, shall conform to BS5550-5.1.1:1978. 3.4 The film shall have a minimum of2.0m of leader ahead of the first frame of the test film
17、itself. 3.5 The film shall have a minimum of2.0m and a maximum of10.0m of trailer following the last frame of the test film itself. 3.6 The length of the test film, excluding leader and trailer, shall be a minimum of50m. 3.7 The test film shall be lubricated to ensure maximum film life and trouble-f
18、ree passage through a projector. 3.8 Both the leader and the trailer shall be marked to identify the test film as the picture test film specified in this British Standard. In addition, the leader and trailer shall be identified as head and tail respectively. 3.9 The full length of the test film, if
19、necessary excepting leader and trailer, shall be free of splices. 4 Frame dimensions and positioning 4.1 Dimensions of frames The frames printed on the test film shall conform to the dimensions specified in BS5550-2.2.1:1978. 4.2 Accuracy of frame positioning 4.2.1 The nominal position of the frames
20、 shall be the “reference position” as specified inFigure 1 andTable 1, within the basic tolerance as given inTable 1. Table 1 Reference position and tolerances on positions of successive images 1) For information on the availability of artwork from which the test film can be made, apply to Customer
21、Services, Information, BSI, Linford Wood, Milton Keynes MK146LE, quoting the number of this standard and the clause number referring to the item concerned. Dimensions for reference position Basic tolerance on reference position Tolerance on accuracy of successive images within test film (seeFigure 1
22、) C = 7.98 mm (0.314 in) 0.012 mm 0.005 mm K = 4.445 mm (0.175 in) 0.012 mm 0.005 mmBS5550-2.12.1:1993 2 BSI 10-1999 4.2.2 Throughout the length of the test film the position of each image shall not vary, frame to frame, from the nominal position by more than 0.005mm as given inTable 1. 5 Test patte
23、rn 5.1 The test pattern shall be produced as artwork from which the test film is shot and this shall be either on a transparent base or on opaque material. NOTEA transparent base might be preferable if the speed of a suitable film stock having the required resolution capability is slow. 5.2 The test
24、 pattern shall contain components to allow tests to be made of vertical and horizontal unsteadiness, vertical and horizontal alignment, resolution at the centre part and at each of the corner parts of the projected image, ghosting, magnification, flare and astigmatism. 5.3 The test pattern on the fi
25、lm shall consist of clear lines on a black background, and the components of the test pattern shall be placed on the frame as shown inFigure 2. 6 Components of the test pattern 6.1 Camera-image border, in conformance with BS5550-2.2.1:1978. 6.2 Projectable-image border, in conformance with BS5550-2.
26、2.2:1978. 6.3 Steps on borders, to judge accuracy of aperture in projector and its alignment with respect to the film guides and the film pull-down mechanism. (SeeA.5.) 6.4 Marks on vertical borders, to test the amount of framing adjustment on the projector above and below the nominal position. (See
27、A.6.) NOTEThis test is specified in clause10 of BS5550-2.7.2:1982. 6.5 Sets of resolution patterns in the corner and centre parts of the frame, to check the image resolution. (SeeA.9.) 6.6 A circular resolution target, at the centre of the frame, to aid accurate setting of best focus at centre and f
28、or evaluating astigmatism. (SeeA.9.) 6.7 Graduated triangles, for checking vertical and horizontal picture unsteadiness. (SeeA.7.) NOTEThis test is specified in clause 21 of BS5550-2.7.2:1982. 6.8 Rectangles, for evaluation of travel ghost and image flare. (SeeA.8.) NOTEThe test for travel ghost is
29、referred to in clause 22 of BS5550-2.7.2:1982. 6.9 A bar, 1mm long, for making a direct measurement on the screen of image magnification. (SeeA.6.) 6.10 Lines of the “mire”, for subjective evaluation of overall focus. The mire shall be as specified in BS4189:1967. Figure 1 Accuracy of the position o
30、f the frame of the image on the test filmBS 5550-2.12.1:1993 BSI 10-1999 3 NOTEThe test film will be a negative of the above figure Figure 2 Appearance of the frame on the test film BS5550-2.12.1:1993 4 BSI 10-1999 Annex A (informative) Guidance on the use of the 16 mm motion-picture test film A.1 C
31、are should be taken to ensure that the projector is set up in accordance with the measurement conditions specified in clause 4 of BS5817-20:1987 before any tests are made using the test film. However, in circumstances where the projector is installed in a film theatre in such a way that the above me
32、ntioned specifications are not precisely and fully met, the tests should be made with the set-up in accordance with the installation design. In such circumstances, it may not be possible to ascribe some of the results of the tests to the projector alone, but to the complete installation of which the
33、 projector is an important component. A.2 The test pattern should be as given in clause5. A.3 It is advisable that users of the test film are well acquainted with BS5550-2.7.2 and BS5817-20. A.4 Before threading the test film into the projector, thoroughly clean the film path and then check that fil
34、m can be safely transported through the projector without damage by the use of an appropriate length of a similar type of film stock to that on which the test film has been made. NOTEThe test film specification has no requirement specifying the type of film stock to be used, except for dimensional s
35、pecifications. However, it is desirable that the test film should meet the requirements of either BS5699-1 or BS5699-2 when processed. If any particular projector is likely to be used exclusively or predominantly for film stock on one particular type of base, e.g. polyester, it is desirable that the
36、 projector should be tested using a test film on the same, or an equivalent, type of base. A.5 The test film frames have two concentric borders. The outer border is that specified for cameras, whereas the inner border is the projectable image border specified in BS5550-2.2.2:1978 and which is contro
37、lled by the aperture plate in the projector. (See clause 9 of BS5550-2.7.2:1982.) The first test made on the projector using the test film should be to see that, with any built-in adjustment facility provided, the projector can accurately project the projectable image border properly centered in the
38、 projected aperture. Staggered steps at the centre of each of the four sides of the border provide a method of judging the accuracy with which the projector projects the projectable image. The steps are each0.025mm, that is,0.259% of the nominal width of the projectable image and0.345% of its height
39、. A.6 Among the adjustments referred to inA.5 there should be a racking or “framing” control. This is a user control the purpose of which is to enable the projected image to be centered properly in the vertical plane. The nominal position of frames on a length of film with respect to its sprocket ho
40、les is permitted to vary within a specified tolerance, although variation from frame to frame within the same film has to be kept within a much tighter tolerance. Short horizontal bars towards the corners of the frames of the test film provide a means of measuring the range of adjustment provided by
41、 a framing control. (See clause 10 of BS5550-2.7.2:1982.) To check the actual adjustment range, first measure the horizontal length of the clear bar in the lower right-hand part of the protected image. The horizontal length in millimetres is the magnification (M) of the film frame. The range of adju
42、stment provided by the framing control is the movement on the screen of the short horizontal barsin mm (achieved by adjusting the control) divided by M. A.7 For picture steadiness tests, which are actually measurements of picture unsteadiness, there are two very narrow triangular-shaped wedges, with
43、 five index marks. The wedge which is vertical in the upper right-hand part of the frame is for measuring weave. Weave is horizontal unsteadiness. If the image of this wedge on the screen is moving sideways over a distance equal to its width at the index mark identified as0.2%, then the horizontal u
44、nsteadiness is0.2% of picture width. The wedge which is horizontal in the lower left-hand part of the frame is for measuring jump. Jump is vertical unsteadiness. If the image of this wedge on the screen is moving vertically over a distance equal to its height at the index mark identified as “0.2%”,
45、then the vertical unsteadiness is0.2% of picture height. NOTEVertical and horizontal unsteadiness are specified in clause 21 of BS5550-2.7.2:1982. A.8 Inaccuracy of timing between the light shutter and the film pull-down mechanism in a projector will cause ghosting of parts of the projected image. (
46、See clause 22 of BS5550-2.7.2:1982.) This ghosting will usually be seen either at the top of the projected frame, or at the bottom, dependent on the direction of the timing inaccuracy. The cause might be faulty design or incorrect assembly or adjustment.BS5550-2.12.1:1993 BSI 10-1999 5 Two sets of c
47、lear rectangular blocks, one at the top of the frame and the other at the bottom, are provided to allow subjective evaluations to be made of ghosting. If one set shows any trailing light over what should be the black background, timing is incorrect and needs to be corrected if possible. If both sets
48、 of blocks show trailing light there is a serious fault in assembly or design of the projector. A.9 Sets of parallel bar patterns are at the four corners of the frame and towards the centre. The nominal values of the patterns are33,40,50,56,66 and80 line pairs per mm. At the centre of the frame ther
49、e is a radial pattern having a continuously increasing frequency of detail from about13 line pairs per mm at its circumference to about85 line pairs per mm. To make a measurement of resolution the image on the screen should be focused as sharply as possible at the centre of the frame. Each of the sets of parallel bar patterns should then be inspected at the screen, starting with the least detailed (33 line pairs permm), to determine at which frequency the resolution in either the vertical or horizontal plane fails. The resolution would then be rep
