International projectionist (Jan-Dec 1947)

own frame line shows inside the masking. The result will be a fuzzy edge at one or both sides of the picture, and the picture may appear to be unsteady. Travel-Ghost Target This target will show improper timing of the shutter by showing a fuzzy outline on the several "T" patterns, with a pronounced "Christmas Tree" effect above or below the horizontal lines and in line with the uprights of the "T's". Fuzzy outlines or travel-ghost "tails" appearing above some or all of the patterns indicate that the shutter is closing too late. (The film has started to move before the shutter closes.) Travel-ghost "tails" appearing below the patterns indicate that the shutter is opening too soon. (The shutter has opened before the film has stopped moving.) As travel-ghost is reduced by adjusting the shutter, the tails will gradually disappear, and a slight further adjustment of the shutter control should make the previously fuzzy lines crisp and clear. In some rare cases it is possible that no position of the shutter control will completely eliminate travel-ghost. In such an instance the shutter blade is probably effectively too narrow and a more serious correction is required. Jump-and-Weave Target This target will show the amount of projected picture unsteadiness, measured in per cent of picture height for jump and in per cent of picture width for weave. Each step of the triangular white areas at the top and bottom of the screen represents 1% of picture height. This makes it a simple matter to estimate the amount of jump in fractions of a per cent. Opening and closing of the white areas can be judged best by an observer standing just far enough back from the screen so that color fringes are not readily apparent. Weave may be determined in the same way, because each step of the triangular white areas at the sides of the screen represents 1% of the picture width. When adjusting to reduce unsteadiness of a projector head, be sure to follow the recommendations of the manufacturer for the particular type or model of projector. Gate tension, loop size, intermittent sprocket wear, wear of the intermittent Care of Test Films REMEMBER— Test films are precision tools and must be handled with care. 1. Keep them clean. 2. Use as often as required, but do not run them unnecessarily. 3. When you finish a test run, rewind the film with firm tension on its original reel. Replace with a reel band, in its original can, tape the can securely and store it in a safe, cool place. When Ordering Visual Test Film or Replacements Orders for the visual test reel should be designated at follows: Research Council — SMPE 35-mm Visual Test Film and should be sent to either the Society of Motion Picture Engineers, Hotel Pennsylvania, New York 1, N. Y., or the Research Council, Academy of Motion Picture Arts & Sciences, Taft Building, Hollywood, Calif. Price: $17.50 complete, including shipping charges within the U. S. A. Additional charge for export shipping. When ordering replacement loops of target patterns designate as follows: 1. 35-mm Visual Test Film: Focus-andAlignment Section 2. 35-mm Picture Test Film: Travel-Ghost Target Section 3. 35-mm Picture Test Film: Jump-and-Weave Target Section Order any length desired from 100 to 900 ft. in multiples of 100 ft., at $5 per 100 ft. The most suitable and convenient length at reasonable cost for average use is probably 200 ft. movement, and movement or vibration of the entire projector may all contribute to unsteadiness of the picture on the screen. As many of these obvious causes as possible should be checked and eliminated before contemplating any expensive overhauling to improve performance. Separate lengths of the Jump-andWeave target, where used, should be run full length and not as loops, because in a loop the large black area will get very hot, with increasing tendency to shrink and buckle, making the test unreliable. If used, handled, and stored correctly, the film should last a long time, but should be replaced as soon as it begins to show signs of wear or buckling. Lens-Aberrations Target This target will indicate fall-off in sharpness over the screen by a fuzziness TRAVEL-GHOST TARGET of the vertical and horizontal lines, and this indicates the lack of sharpness present in pictures shown on that same projector. Distortion (the curving of straight lines) at top and bottom of the screen is shown by the horizontal line pattern; while the same effect at the sides of the screen is shown by the vertical line patterm. Cleaning, accurate focusing and correct alignment of the optical system are about all that can be done to improve optical performance. Because it is not necessary to run the film while making such adjustments, separate sections of this target have not been made available. JUMP AND WEAVE TARGET Altec's ED-35 Sound System Transmission Test Film A new ED-35 Transmission Test Film has been developed by the Altec Service Corp. with the aid of the Academy of M. P. Arts & Sciences and the S.M.P.E. This new film is of laboratory precision, is printed on safety stock and contains two sound tracks. One track, entitled "Multi-Frequency Test," starts with a short section of "buzz track" to indicate whether the guide rollers of the film reproducer are correctly set. Following this section is a series of constant frequency sections in this c. p. s. order: 100, 40, 70, 130, 300. 500, 2000, 3000, 7000, and 8000. For the convenience of the serviceman, the low frequencies are recorded at reduced level, and announcements precede all sections except for a few of the higher frequencies. The interval between 7and 8000 cycles consists of unmodulated track exposed to a density equal to the average density of the recorder sections to permit the evaluation of the effect of film noise on the readings. New Technique Assures Accuracy The second section is entitled "Flutter Test" and contains a strip of 3000-cycle sound and a section of sustained chords (Continued on page 26) 12 INTERNATIONAL PROJECTIONIST April 1947