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Scratch Test: Difference between revisions
→Methods
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==Methods== | ==Methods== | ||
General | ===General=== | ||
It is helpful to do a deep and thorough clean of your projector before a scratch test. | |||
If evaluating for scratches on screen, use a full aperture lens and plate so that the maximum possible image area (including the soundtrack) is visible. | If evaluating for scratches on screen, use a full aperture lens and plate so that the maximum possible image area (including the soundtrack) is visible. | ||
Because film behaves differently when running at full speed, advancing a scratch test by hand is not sufficient. Advancing by hand may be useful in determining if a roller is scratching film, but not so much for determining if your lower loop is hitting the bottom of your intermittent casing, for example. | Because film behaves differently when running at full speed, advancing a scratch test by hand is not sufficient. Advancing by hand may be useful in determining if a roller is scratching film, but not so much for determining if your lower loop is hitting the bottom of your intermittent casing, for example. | ||
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===Visual Evaluation of Film Path=== | ===Visual Evaluation of Film Path=== | ||
Because the above tests do not take into consideration running a full reel of film, and it would be impractical to use 2000' of expensive film stock to run a scratch test several dozen times, a careful and thorough check of a known good test reel should conclude the scratch testing process. Run a full reel of film and examine the film path as it plays: Are all rollers turning? Are the arms aligned so that the film is completely clear through the entire reel? Is the film entering the projector evenly? Look for any new scratches or other issues on your test reel. | Because the above tests do not take into consideration running a full reel of film, and it would be impractical to use 2000' of expensive film stock to run a scratch test several dozen times, a careful and thorough check of a known good test reel should conclude the scratch testing process. Run a full reel of film and examine the film path as it plays: Are all rollers turning? Are the arms aligned so that the film is completely clear through the entire reel? Is the film entering the projector evenly? Look for any new scratches or other issues on your test reel. | ||
==Diagnosis== | ==Diagnosis== | ||