1、1 ScopeThis practice recognizes that proper lubrication of35-mm motion-picture prints is needed to promotegood projection performance. Proper lubrication willresult in improved steadiness, reduction of noise inthe projector gate, reduced perforation damage, andincreased projection life.2 Normative r
2、eferenceThe following standard contains provisions which,through reference in this text, constitute provisions ofthis practice. At the time of publication, the editionindicated was valid. All standards are subject torevision, and parties to agreements based on thispractice are encouraged to investig
3、ate the possibilityof applying the most recent edition of the standardindicated below.SMPTE RP 48-1995, Lubrication of 16- and 8-mmMotion-Picture Prints3 Definitions3.1 edge waxing:The application of wax orother lubricant to the area of the processed printfilm that is outside the picture and sound t
4、rackarea. On 35-mm film, lubrication is usuallyapplied to each edge, including the perforationarea and margin, using a suitable applicatorwheel. The high level of lubrication required by35-mm prints usually requires edge waxing.3.2 full-width lubrication: The lubrication of theentire surface of the
5、film, including picture andsound track area. Usually the film is dippedin a solvent solution of the lubricant, buffed,and allowed to dry. Full-width lubrication isrecommended for 16- and 8-mm motion-pictureprints, as noted in SMPTE RP 48. The amountof lubricant that can be applied to the film as afu
6、ll-width application is limited because of prob -lems with mottle, visibility, and roll slipperiness,and is usually insufficient for optimum projectionlife of 35-mm prints.4 Lubricants4.1 Recommended lubricantA solution of a hard wax dissolved in a suitable solventis the recommended lubricant. No ot
7、her wax or lubri -cant was found in the literature to be as safe, effective,or inexpensive as paraffin wax. The most commonlyused solvent for dissolving and applying the wax isinhibited methyl chloroform (1,1,1-trichloroethane),a solvent often used for cleaning motion-picture film.Proper care should
8、 be exercised in handling thissolvent, to minimize exposure of personnel orenvironment to the solvent or its vapor. An inhibitedgrade of solvent should be used to minimize thepossibility of solvent decomposition and the releaseof toxic fumes.4.2 Unsuitable lubricantsThe lubricant and solvent used sh
9、ould have noadverse effect on the film, and should be effective inprolonging the projection life of the print. Mineral oils(motor oil, projector oil) may dissolve and leach outthe oil-soluble dyes in the film, and should not beused. Nonvolatile oils (mineral or silicone) may causemottle or undesirab
10、le sticking together of the filmsurfaces, which may cause dirt particles to adhereto the film. Some materials may attack the film baseor emulsion, or have an adverse effect on imagestability or projection life. Avoid using solvents thatare flammable or explosive, or that pose a health orenvironmenta
11、l hazard (e.g., benzene or carbontetrachloride).Revision of RP 151-1994RP 151-1999SMPTE RECOMMENDED PRACTICEApproved April 23, 1999Copyright 1999 by theSOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS595 W. Hartsdale Ave., White Plains, NY 10607(914) 761-1100Lubrication of 35-mm Motion-PicturePrin
12、ts for ProjectionPage 1 of 2 pages5 Film cleaningThe lubricant should be removable by normal film-cleaning operations, such as solvent cleaning. Aftercleaning, the film should be relubricated prior to thenext projection.6 Edge-waxer designThe edge wax is usually applied to the film at a pointnear th
13、e end of the processing operation, using anapplicator wheel rotating in a reservoir of edge-waxsolution. The applicator wheel applies the wax solu -tion only to the perforation and margin area of the film.The wax solution is usually applied only to the emul -sion side of the film, with some transfer
14、 of the wax tothe base side of the film expected when the film iswound up into a roll. The wax solution is allowed topartially dry on the film prior to wind-up, so it will notmigrate into the picture or sound track area.Many laboratories apply edge wax to the film just priorto the film wind-up on th
15、e processing machine. Equip -ment is available from several suppliers, or may becustom built. Care should be taken to monitor andcontrol the application of the edge wax.Edge wax may also be applied to the processed filmas a separate operation, using equipment that iscurrently available.7 Edge-wax ap
16、plicationThe amount of wax applied to the film is a functionof the concentration of the edge-wax solution, theapplicator wheel speed, the film transport speed,and the surface properties of the applicator wheel.Concentra tion of up to 50 grams of wax per liter ofsolvent may be used with the optimum c
17、oncentrationdependent on applicator design, machine speed, andeffectiveness of the final result as described in clauses8 and 9.Edge wax should not be applied to prints which willlater have magnetic striping or protective overcoatsapplied, as the wax will prevent proper adhesion ofthese materials. Ed
18、ge wax should not be applied to35-mm film which will be slit for 16- or 8-mm use.These films should be lubricated in accordance withSMPTE RP 48. Edge waxing is not necessary forprints intended only for use on continuous motiontelecines.8 Properties of properly edge-waxed filmThe dried wax deposit sh
19、ould be just visible as a hazeon both the emulsion and base side of the film. Thewax deposit should be only in the perforation andmargin area, and should not bleed into the picture orsound track area. When wound with normal tension,large rolls of film should not dish when handled, andthere should be
20、 no excessive build up of wax duringprojection.The effectiveness of the lubrication in prolonging pro -jection life should be evaluated by using the FilmProjection Life T est (see clause 9). Properly lubricatedprints should have at least twice the projection life ofunlubricated prints. Insufficient
21、wax application willgive less than optimum performance. Excessive waxapplication may intrude into the picture or sound trackarea, or result in wax flaking or buildup in the projector.9 Test methodsThe Film Projection Life Test is the most reliablemethod for determining the effectiveness of the lubri
22、 -cation in improving projection life. Simple measure -ments of the coefficient of friction of the emulsion andbase side of the film (e.g., paper-clip friction or sledfriction) may not accurately measure the effectivenessof the film lubrication in actual use, although they maybe of use in monitoring
23、 wax application.The Film Projection Life T est is fully described in thereference given in annex A.Annex A (informative)BibliographyMino, Edward and Perry, R. S. Lubrication of 35-mm releaseprints for extended projection print life. SMPTE Journal92(10):1051-1057; October 1983.RP 151-1999Page 2 of 2 pages
