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HOW TO USE YOUR COMPCO "500" STEREO PROJECTOR

Congratulations -- if this is your first stereo projector you are in for a new thrill when you see your first stereo slides on the screen as large, almost life-size images with depth and in rich natural colors. Now, it is no longer necessary to restrict the enjoyment of your slides to the limiting confines of the handviewer. The"500" permits large and small groups in homes, schools, churches or business meetings to see the same vivid three dimensional projected images at the same time, and opens vast new possibilities for the increased use of stereo photography in education, training and sales activities.

To make the best use of your projector it will be necessary to follow a few simple rules as outlined in this booklet. We make no attempt to instruct you in all the theories covering stereo photography and projection, but rather to give you the basic information in concise form which will permit you to project your slides with a minimum of adjustment and effort.

Current supply - The "500" Stereo Projector operates on standard 110-125 volt, 60 cycle, Alternating Current only and uses two 500 Watt lamps. Important: Do not use on Direct Current or other voltage or other cycle current as it will burn out the blower motor. Special models are available for other current requirements.

The brightest image will be obtained if the room is well darkened, although some types of screens are designed to yield a good image in conditions of relatively high levels of illumination. Generally it is necessary to block off day light or other extraneous illumination when the conventional silver screen is used.

Because stereo projection makes use of polarized light which will reflect only from a metallic surface, you must use a special screen having an aluminum coated surface which can be stretched perfectly flat and free of wrinkles. Some screens require a stretch out period to become perfectly flat and should be set up well in advance of use. Stereo screens are readily available from your dealer and come in sizes 40" x 40", 50" x 50" and larger. Ordinary beaded or non metallic screens cannot be used as polarization will be lost and you will see "double" images even when wearing your polarized viewing glasses.

Observe that your Compco "500" Projector has two lenses and two complete optical systems which enables you to project the two separate images of your stereo slide. Each optical system polarizes the light in a different direction so that when you view the image on the screen thru your polarized glasses, your right eye sees only the right picture and the left eye only the left picture. Without glasses you will see a double image. Ordinary polarized sun glasses will not work; you must have glasses polarized to the same angle as used in the projection system. One pair of permanent type plus 6 pair of semi-permanent viewers are supplied with each Projector; additional viewers may be purchased from your dealer. We strongly advise the purchase of the permanent type, although some what more costly because the polarizing material is laminated between protecting glass lenses and thus can be cleaned without injury and, consequently, used indefinitely. If you normally wear correction spectacles you can place your polarizing viewers right over your regular glasses.

Most people will find that a distance between eight and fourteen feet from a 50 inch screen is satisfactory; for a 40 inch screen slightly closer. If your audience is too far back from the screen certain objects may appear unduly elongated and the remedy is to arrange seating that will avoid this. Try to have audience as close to the axis of projection as possible, since we are dealing with a reflected image from the screen and the brightest picture will be seen by those directly in front of some part of the screen rather than at an offside angle. Center-line seating also minimizes angular distortion.

Provide yourself with a solid table or stand so that when you change slides your audience will not see a "jiggled" picture on the screen. Any image movement is very disturbing and must be avoided. The Compco "500" has three point base support which is self adjusting to an irregular surface, however, if your table slopes it may be necessary to level the projector with relation to the screen by placing a piece of cardboard under one projector foot. With the standard 4 inch projector lenses you will fill a 40 inch screen by placing your projector approximately 15 feet from the screen; for a 50 inch screen the distance is about 19 feet.

Even though your room may not permit the maximum projection distance you can still enjoy reasonably large pictures at shorter distances, for instance, with. only 8 to 10 feet projection distance your screen image will be about 27 inches wide. If possible, set up your projector and screen well in advance of a showing so that you will have time to make a "practice-run" and preview your slides.

A slide carrier for stereo 1-5/8x4" slides, is supplied with each"500" Projector, and it is packed separately in the carton in which you received your projector. It is a precision machined unit, engineered and manufactured to very close mechanical tolerances. Handle it with the same care that you give your camera and always replace it in the special compartment in the Projector Case when storing away your projector.

First, remove the locking screw from the upper channel. This locking screw is provided for automatic slide changers and should be removed completely when not in use. Hold the carrier by the solid portion with the slide opening compartments facing you and the open end upward. Notice that at both ends there are small metal buttons called "Ejector Buttons". These serve a dual purpose both as stops to limit the carrier travel and to eject the slides for removal. Now, hold down on one of the Ejector Buttons and insert the end of the carrier into the carrier channel on the projector. You should now be able to push the carrier all the way thru the channel by a light pressure of the finger on the operating handles. Move the carrier back and forth several times to make sure it operates freely and smoothly. (If any binding occurs it is probably because the locking screw on the upper channel is turned down too far if it has not been removed.)

Slides may be inserted from either right or left sides, as you face forward and stand in the normal operating position behind the projector. Move carrier to extreme right or left side and place your first slide in the carrier with image upside down and emulsion (dull) side toward the screen. Make sure that the slide is firmly seated in the carrier-press down firmlyThis is very important for good registration. When using paper type slide mounts, be sure mount is seated in carrier with both edges toward lenses.

Now push the carrier to the other side until it stops, by a light finger pressure on the operating handle. Your first slide is now in projection position. Note: The action of moving the slide carrier by operating handle automatically operates the built-in "black-out" shutter and eliminates the disturbing element of seeing the slides move and blur as you change them.

Located on the side of the projector, the control panel provides Switches for Lamps and Blowers; an Accessory Outlet with Switch; a Switch for controling the Electronic Shutter, and the Focus Control Knob.

Two switches are provided for this purpose. One switch for each optical circuit, with three positions. Bottom position is "off", Center position Blower or Fan only "on". Top position, "on" for both lamp and fan. The Projector is so wired that you cannot turn lamps on without blower operating. The blower, however, can be operated independently, of the lamps and thus cool the projector after use. It is recommended this be done after showing to lengthen lamp life. It is recommended that these switches be in "off" position when inserting cord set into electrical outlet.

This outlet is provided for plugging in a table or floor lamp with a maximum of 60 watts, for convenience lighting between showings, and is controlled at the projector by the Switch-marked "Accessory".

Located at the extreme right end of the Control Panel, this switch controls the Electronic shutter action of the Projector. In all Stereo projection the switch should be down in the "Stereo" position. When it is desired to project 2" x 2" (35 mm) Slides, then the switch would be placed in the "35 mm" position.

The location of the polarizing filter in the "500" is unique in that it is placed between the slide and projection lenses. This has the advantage. that all light passing thru the slide is polarized regardless of whether your slide is mounted in a depolarizing material or not. Filter is protected by glass and mounted in a metal frame so designed that it will fit into the slotted receptacle located in the lens housing only in the proper polarizing position. When setting up your projector for stereo slides always make sure that the polarizer is clean and that it is in its proper position. The filter may be cleaned in the same manner as a lens or pair of spectacles.

With your first slide in projection position, turn only one lamp on (top switch position) and you will see one side of your stereo slide projected in conventional 2 dimensions. By turning the knob marked "focus" at the side of the projector you will be able to bring the image into sharp focus on the screen. Since both lenses are focused simultaneously, both images of your slide will automatically be in focus."500" projector lenses are carefully matched before leaving the factory, however, they might become loosened in shipping and it will be best to check for focus on both images by switching off one lamp and switching on the other. If any variation in sharpness is noted, check the lens mounting to make 'sure that it is firmly seated in its position. When removing lenses for cleaning, take care to replace them in their original positions. If other lenses than original factory equipment are ever substituted it may be necessary to match-focus by rotating lens barrel. Your dealer will advise you on this.

Up to now you have projected only one side of your stereo slide. Now switch on the other lamp so that both parts of your slide are on the screen. Most likely the two images will be out of alignment, that is, one picture will be higher than the other and separated horizontally and it will be necessary to bring them into proper register. (You can usually accomplish this adjustment better without wearing your viewing glasses so leave them off for the moment).

Your"500"projector provides for alignment adjustment, both vertically and horizontally, by means of one knob control located conveniently near the front of the projector near the lenses.

As you watch the two pictures on the screen, grasp the alignment knob and move it slowly up and down, notice that the images also move in the vertical direction. Make your adjustment so the horizontal line of the "window frame" at either top or bottom of the picture is brought into exact alignment. See sketch.

Using the same knob as for vertical adjustment, make your horizontal adjustment by turning the knob clockwise or counterclockwise and bring the vertical edge of your window frames into alignment. Be careful to avoid changing your previous vertical adjustment or you may need to readjust it. Whether you make your alignment adjustment in the vertical or horizontal first, is of no importance just so that both are made reasonably accurate.

You can now put on your polarized viewing glasses and see your stereo slide on the screen with all its natural color in three dimensions! There are many theories of image alignment in projection---The "windowframe" method of alignment is suggested here because it is one of the easiest methods devised and is quite satisfactory when the projected image is no larger than the 50 inch screen. When larger projections are made it would be well to align on infinity images holding the separation to 2 1/2 inches in the normal direction of separation.

Note: The vertical adjustment is the most critical - most of your audience will not feel any discomfort if even a large amount of horizontal error is present. Always avoid making adjustments while your audience is viewing the picture as many people find it extremely disturbing.

You may want to raise or lower the projected image on the screen. A locking mechanism is located on the front end of the projection base. Instant adjustment is made by grasping the lower edge of the base between the fingers and lifting it slightly to the position desired, then rotate the knob counter clockwise to release the button and the elevation screw will drop to the point selected. Rotate knob clockwise and the elevation screw will be locked in place.

Always disconnect projector from electric outlet. Grasp the lamp house then lift up and off. When replacing lamp house be sure the three pins locate in retainers and press down firmly.

(For the following 2 sections, you may want to refer to this Detailed Drawing)

Disconnect line cord and be sure lamps are cool. Remove lamp housing. Lamps are now accessible and may be removed by grasping the top and pull upward to disengage. It is advisable to replace both lamps when one burns out in order to maintain uniform illumination of both images. Replace with standard 500 Watt, 115 or 120 Volt medium prefocus base projection lamps Sylvania CZA. It is suggested that you keep an extra pair of lamps on hand for "spares".

Note: Lamps larger than 500 Watt are not recommended.

Remove lamp housing. Notice that each condenser and heat filter is held in place by individual flat hold-down springs to allow for separate heat expansions. These retainer springs may be removed by pressing down on one side to release bottom clip. Each condenser and heat filter may be removed from its receptacle and cleaned with lens tissue or a soft lintless cloth, such as an old well washed linen handkerchief. Avoid finger contact with the actual cleansing surface of the cloth or tissue and handle glasses by their edges. If grease or oil smears are present, remove by washing with mild soap and water or with alcohol.

All four condensers are interchangeable with each other but must be replaced in proper position with sides of greatest curvature facing each other. Heat filter is located nearest projection lamps. Two heat filters one in each optical system, are supplied.

Remove one lens at a time by rotating lens barrel counter clockwise. To clean, first remove dust with a soft lens brush - this is important so that the abrasive action of the dust does not scratch thru the anti-reflection coating on the glass-air surfaces. Clean lens surface with lens tissue or lintless cloth. Smears may be removed with a cotton swab slightly moistened with one drop of pure alcohol. Replace lens in the same position as before since lenses are focus-matched at factory.

After each 500 hours use or every three months, whichever occurs first, lubricate blower motor with two drops of light machine oil placed in both top and bottom bearings. Motor is accessible by removing six screws in the base plate and lifting entire base plate assembly off base casting. Be sure to disconnect line cord before removing base plate.

Your Compco "500" is a dual purpose projector. In addition to stereo slides it can be converted, in a matter of seconds, to show conventional 2 dimension slides. The polarizing filters are located out side of the lamp housing - instantly removable, permitting the full brilliance of the 500 watt lamps to be used. A carrier for conventional 2 x 2" slides is also available at slight extra cost. Also of precision design, it will fit the Compco `500" unit exactly without adaptors. When projecting the 2 x 2" slides, insert carrier in track as is done with the stereo carrier, and if operating from the right side of the projector, insert slide in aperture at the right end of carrier, press shutter switch to 35 mm position, turn right lamp on, push carrier to the left of its stop and view. While viewing, second slide can be inserted in the left hand aperture of the carrier and move carrier to the right. By alternating back and forth, slides can be inserted in carrier while other slide is being viewed. This provides semiautomatic operation with the viewing time being determined by the length of time required to insert second slide, and move carrier. Be sure to remove filter from lens housing, first. Your Compco "500" will also accommodate the Airquipt Automatic 2 x 2 slide changer without adapter just insert on right side and fasten in place with locking screw provided, use only right lamp.

Although the Compco "500" will project all types of stereo slide mounts in the 1-5/8" x 4" size, you must remember that in projection any inaccuracy in mounting will be magnified many times. Many mounting errors can be compensated for by the alignment adjustment of the projector lenses - but who would want to sit thru a series of slides in which almost every other slide would require an adjustment to be made. Probably most of your slides were made for use in a handviewer where the tolerances are not critical and when you attempt to project them you will find that most of your slides are not in good alignment with each other. It may not be necessary to remount all of your slides but for the benefit and viewing comfort of your audience and yourself we strongly urge you to - preselect your slides - This simply means that in advance of your "show" that you run your slides thru the projector and those that fall into one alignment adjustment group be kept separate from another alignment group. You might even identify the slides of each group with a bit of binding tape of a different color or by a number tab. Now when you project the slides for your audience you will need to make the alignment adjustment only for each group. Some slides may appear very uncomfortable to the eyes when projected and these should be set aside for remounting.

THE GOLDEN RULES OF STEREO PROJECTION

1. Be sure your Compco "500" Projector and slides are perfectly clean throughout.
2. Use only a metallic surfaced screen of perfectly smooth surface.
3. Provide your audience with the best viewing glasses you can obtain, clean and unscratched.
4. Preview and preselect all slides you intend to show.
5. Align the projector before your guests arrive.
6. Insert each slide upside down, emulsion side toward screen.
7. Be sure the slide is firmly seated in the slide carrier.
8. Try to avoid projection of any one slide for more than 20 seconds.
9. Never touch the alignment controls while spectators are wearing their viewing glasses.
10. When writing to the factory regarding your "500" Projector, please indicate serial number shown on base plate under lamp cover.