Page 13 - SAFAR

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It is a common fault to run a loudspeaker at a higher volume setting than is
necessary. It will be found that audiences naturally adapt themselves to the volume
level; a high level will result in a fidgety audience who will make no attempt to keep
quiet.

Observe at all t imes that the screen image is framed and focussed correctly. It
is a common error to show a picture that is too large for the size or placing of the
audience. The size of the screen is directly governed by the distance from the pro-
jector, size of lens in use, and the location of the audience. When selecting a screen,
bear in mind that nothing is worse than a small picture marooned in the middle of a_
large screen surrounded by a dim white border. Choose a screen of such a size that
at the projection throw contemplated the picture will fill the white area with a sharply
defined frame outlined by the black masking. Such a picture will appear infinitely
more crisp and pleasant than the first. If the screen is too large, improvised masks
should be made from black material or paper of low reflective value.
It is preferable, if a larger picture is required, to use a lens of shorter focal-length
rather than to inc rease the throw excessively.
The min imum w idth of the screen should be taken as one-ninth of the distance
from the screen to the back row of the aud ie nce; the distance from the ft·ont row of
the audience should not be less than 2 t o 3 times the width of th e screen, whilst the
angle of vision from the front row to the top of the screen shou ld not be more than
about 35-40°. The seating should be arranged to compl y with these conditions.

CLEANING : The projector shou ld be kept free fro m dust, dirt an d damp at
all times. Keep the doors closed ·when not in use; indeed, the doors need only be
opened for threading , use of mechanical controls and maintenance, and should be kept
closed at all ot her times. An exception to th is is the door at t he back of the loud-
speaker cabinet , w hich should be left w ide open during projection.
Exam ine the projecto r carefuliy afte r every performance, an d, if necessary, clean
the gate, sprocket and rollers, etc. Remember to use on ly scrapers of bone or plastic,
or wood, etc. , and never one of metal.

All optic surfaces, comprisi ng t he reflector, lamp buibs, condensers, pris m, objec-
t ive le ns, sound- reader optic un it, etc., shou ld be clean and free from d ust. Lenses,
comprising the objective lens, cond enser, prism and sound-reade r unit , should be
cleaned with proper lens tissue only and un due pressu re should be avoided. On no
account use any cleaning compounds or solvents fo r cleaning glass su rfaces. Do not
attempt to disman tle any lens unit, but co nfin e cleaning solely to the external surfaces.
If, after prolonged use internal faces require attention, t hey should be returned to
the manufacturers or a reputable dealer for clean ing and resealing.

ADJUSTMENTS : if so und definit ion deteriorates, the sound-reader optics unit
· may require realignment. Slacken the two centre screws just suffici entl y to free the
top and bottom eccent ric adjusters and adjust these for optimum results. ThSJ iower
screw head governs the vert ical posit ioning of the unit and thereby focuss~s the