Mounting Stereo Slides This booklet includes articles that have - - PowerPoint PPT Presentation
Mounting Stereo Slides This booklet includes articles that have been published in 4E ! X JOEPX ! the Bulletin of the Sydney Stereo Camera Club website: www.oz3d.info by Allan Griffin and Ray Moxom edited by Ray Moxom, Sydney Australia e-mail:
This booklet includes articles that have been published in
4E!XJOEPX!
the Bulletin of the Sydney Stereo Camera Club
website: www.oz3d.info
edited by Ray Moxom, Sydney Australia e-mail: raymoxom@tpg.com.au
by Allan Griffin and Ray Moxom
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Mounting Stereo Slides Part 1
by Allan Griffin
HonPSA, FPSA
IMPORTANT NOTE: The fundamentals explained in this section by Allan Griffin for cardboard mounts, particularly those relating to the all important “stereo window” and the diagrams on page 8, also apply to mounting in RBT mounts.
Selecting the Best Stereo Mount
28x23
30x20 16x21 30x15
Mount sizes shown are from the RBT range - sizes are in millimetres. Which mount would you have selected for this image? Photograph by Nancy Moxom
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The RBT Plastic Mount Two Way Adjustment System
The illustrations below show the rear (black) half of the mount. After the film chips are aligned, the front (white or ) half of the mount is pressed on to the rear half. I find a small pair of pliers useful to clamp the two halves of the mount together. Firm fixing and adjustment is provided by the use of plastic “pin-bars” which fit nicely into the top and bottom recessed rails. The film chips fit
bars which permit them to be placed as illustrated to achieve a vertical variation of from zero (1) to 0.4mm (5) in 0.1mm increments. (There are
alternative pin bars available that allow adjustments in approximately 0.2mm increments to 0.7mm).
Accurate baseline or vertical registration is achieved by working to a proven jig / grid mounting system or by trial and error, checking progress in your stereoscope (viewer). Free-viewing can also confirm baseline accuracy, particularly if enlarging lenses are
jigs have a light-box under and a pair
When it comes to adjusting for horizontal position, move the chips
to your already proven and preferred method, being careful not to violate the stereo window. As soon as you are satisfied with the adjustment of the film chips, just press the other half of the mount into place on its locating pins. The mount can be easily reopened at any time.
The above diagram was originally published in the September 1991 issue of Stereoscopy
Mounting Stereo Slides - Direct Mounting into Card Mounts
by Allan Griffin HonPSA FPSA
From time to time mounting in card mounts has been taught at the Club as well as privately. However, in view of the fact that we now have quite a few new members, it is appropriate that we again discuss the fundamentals of mounting direct into card. However, it should be remembered that stereo workers tend to develop their own pet technique, and that is good, so long as the end criteria is met, namely:
plane in your stereo slide.
mounting.
horizontal alignment and absence of “twist”).
tape.
so as not to destroy the accurate horizontal seat when placed in the projector. Now, let us get our Gear Ready Here are some items:
make our work less tedious. However, in the meantime, we can make good steady headway without a jig. A thumb gauge will do for starters in applying a reference line.
bind slide mount. Ideal binding tape does not exude adhesive with time and is thin.
frame lines are virtually non-existent compared with 7 and 8 sprocket sizes.
prints on film. I personally don’t use them, but opt rather to use
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clean hands/fingers. For this option, wash hands with hot water and soap before starting and as often as perspiration and/or skin
touching picture areas as much as possible. A clean cloth will remove the odd inadvertent mark if done promptly.
film chips, but rather, always use tweezers for handling.
Back. Now We are Ready to Start Once you get into business, your jig and light box are built as an integral
slide in 3-D as you make your final adjustment for proper window. We will assume that you have no jig but that you do have a light box. All a jig does is hold the mount firm and supply a film base line approx 3mm from the edge of the mount. In your case, use a thumb gauge or other to draw a pencil line 3mm from edge of mount so as to place film chip central over aperture, but first take a good look at the mount. Its front is marked with a couple of indent lines for title. Hold it closed with fold at top. This is the best
with an X. You are to attach chips to back of front half. Lay the open mount face down on light box so that you can attach film chips to back of front half. Draw the 3mm gauge line along bottom edge. Arrange the chips face down so that when mounted and turned over, they will be on their appropriate side properly orientated. Attach the chips to the reference line, at the same time making certain that they are in proper relationship to each other so that the plane of the window is just in front of the nearest item in the stereo picture, unless you especially want to bring a suitable element in the stereo through-the window. This latter case we will consider to be the exception. It is normal, without a jig complete with lenses, to simply pop your slide into your hand viewer to check its accuracy. Now here is a tip for adjusting one or both chips assuming they are not quite right first try. I again use the sharp pencil and draw a reference mark around the chip where appropriate, and after removing the chip, fix it down again in new position in relation to reference mark. Half Glass Mounts RBT also have a range of half glass mounts. The glass is only used on the front side of the mount. While this might give some degree of protection to the film, the rear (emulsion) side remains unprotected. The unglassed emulsion side of the film ensures that the auto-focus in RBT projectors functions seamlessly for a mixed half glassed and unglassed show. Moisture from the air can become trapped between the single glass and the film resulting in moisture patterns on the projected image and possible damage to the slides. This is a potential problem with warmer running older projectors and is not a problem with the cooler running RBT Projectors. While several exhibitions now use RBT projectors (including ISU, DGS, Ohio and Southern Cross), I would recommend that unglassed RBT mounts be used for exhibition slides. If the slide is of particular value, then use a quality dupe when entering exhibitions. Keep in mind that the easiest dupe is always the ‘in camera dupe’ that you create by taking more than one shot when you shoot the original. Fixing Minor Twist The description on the next page of the RBT two way adjustment system will cover the majority of shots taken with a stereo camera or a well aligned twin rig. But, perhaps our wide based twin rig was a little out of line resulting in one film chip having a slight twist relative to the other. This can be fixed as follows:
chip pin on each "mini pin bar"
the "mini pin bar" and/or have one on the top rail and one on the bottom rail to get the required rotation. (Normal pin bars allow adjustments of up to 0.4mm in 0.1mm increments.)
in approximately 0.2mm increments to a total of 0.7mm. Once I had done a couple I found that procedure was quick and worked
that was not rotated. A similar procedure can be applied to both left and right chips to correct slightly sloping horizons.
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If the demand exist, it is just possible that the range of insert masks will be expanded in the future. What sizes would you like to see? How about 28 x 20mm, an offset 30 x 17.5mm, a 20mm circle or a 20 x 30mm ellipse? The possibilities are endless.
Stereo Slide with 2:1 Aspect Ratio (30 x 15mm RBT Mask) Slide by Nancy Moxom taken with her Olympus XA Twin Rig Nancy Moxom Mounting in RBT Mask Insert Mounts Using her SAM Mounting Jig
Many, including myself, find it easy to mount our slides in RBT mounts without the need to use a mounting jig. I just use a small light box and a pair
including Nancy, prefer to use a mounting jig. Here we are assuming you know how to adjust for correct window. If not, see below. Often a re-adjustment requires adjusting baseline at the same time as moving chip in or out relative to the other chip. During the practice runs you will no doubt have several attempts, but it helps no end to have an experienced person around to assess your degree of success or failure as well as give hands-on guidance. Remember, if you are uncertain, work with a tutor. Far too many people go on for years dishing up work which screams from the screen: “I haven’t a clue about what I am doing”! Further, don’t overlook the value of “free-viewing” when mounting. I use it all the time and only use viewer lenses for final critical check. Mounting Gauge Some will say: “Heresy - no mention of a mounting gauge so far”. Quite right! It is conceded that there are times when some people find value in the horizontal and vertical reference lines on a gauge, but I find that use of a gauge as a matter of course in no way ensures satisfactory mounting for good stereo window. Those who insist on using a gauge are often looking for an automatic solution to a problem which required personal judgment. Concerning the b/g and f/g vertical lines etched on most mounting gauges, I find that they are useful, along with the horizontal lines, for alignment of the chips in the occasional night slide where only the black of night exists at the edges of the image area. However, as a general rule, I would encourage the use of the mount itself as the primary gauge. I find it to be the most accurate gauge one could imagine! If you do decide to try using a gauge, beware of the very first trap. Most beginners fail to identify the closest item in the picture, and settle for something/someone dominant in the f/g and allow items nearer the camera like grass, gravel, a tree limb or water to impinge on the window. Now you know what to look out for! Emotional Issue One should bear in mind that each “expert” believes his/her method is best, and that’s fair enough. Here I’m merely saying how I do it and how I teach what essentially is a rather difficult subject. It is all about understanding and controlling spatial relationships, and that does not come naturally to the majority of people.
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Mounting for Window Simply select the closest item in the stereo, preferably near the right or left
and the left side of the right aperture than between this item and the left side
selected closest item and the right side of the left aperture than between this item and the right side of the right aperture. It is now only a question of degree as to how little is “little” etc. in order to place the item in question exactly where you want it relative to the window (I wonder how many beginners can make sense of this lot first up). Direction to Move One Chip (or Both) for Better Window Often after the first attempt, you need to move the subject as a whole fore or aft relative to the window. One should commit to memory a sketch or ditty in order to avoid working by trial and error every time. I like this sketch: Converted to words, it goes like this: A. In order to bring your subject forward (closer to the window), move one or both chips so that they will be closer together (usually just a fraction). B. Conversely, the opposite applies. It has been found that distant scenes without much close subject matter project better when pulled closer to the window in mounting than would be indicated by a mounting gauge. This reduces the tendency for whites to ghost and reduces the necessity to make horizontal projector adjustment. The mask insert mounts are referred to as Type M Mounts. The black (rear)
x 15mm mask is inserted. Unlike the standard range of RBT mounts, which have square corners, the insert mask have small radius rounded corners. Mask insert mounts can be mixed with other RBT mounts for an expanded range of reduced height options. This has become simpler with the newer darker coloured opaque front halves that RBT are now producing.
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RBT’s Extensive Range of 3D Mounts by Ray Moxom
Raumbildtechnik (RBT) from Aichwald, Germany make precision plastic stereo slide mounts in six standard sizes and two mask insert sizes. Standard aperture sizes are 21.5 x 23mm (Realist), 28 x 23mm, 31.5 x 23mm, 33 x 23mm, 21 x 16mm (Nimslo) and 19.5 x 23mm (Realist Close Up),. The currently available mask insert size mounts are 30 x 20mm and 30 x 15mm. RBT’s range of mounts (excluding the 19.5 s 23mm) is shown below. If you shoot your 3D slides using a stereo camera or a well aligned twin rig, then using RBT mounts will be the easiest and fastest method of mounting your stereo slides and will result in superior quality better protected slides when compared with cardboard mounts. Understandably, these rigid plastic mounts are considerably more expensive than cardboard mounts and many stereo workers who shoot several dozen rolls of film each year reserve RBT mounts for their best slides. Beginners will find RBT mounts an easy way to mount their first slides. However, it is important to understand the basic principals explained by Allan Griffin in Part 1 of this booklet - particularly those relating to the ability to see the ‘Stereo Window’. The diagram on page 8 can be a great help with understanding the ‘window’. Never the less, by far the quickest and best way of perfecting your stereo slide mounting techniques are with ‘one-on-one’ tutoring. Do not be afraid to ask for help. “Through-The-Window” Effect The rule at our Club goes like this: If an element in a stereo can be made more dramatic in projection by placing it in front of or through the screen, (assuming the plane of the screen to be the approximate plane of the window) then it should be so mounted. However, all such “through-the- window” subject matter should be clear of the 4 sides of the window and not be amputated or intersected by the window. Range of Mount Sizes
Square format (5 sprocket) Realist etc. Horizontal format (7 sprocket) 21.5 x 23.0 Normal 28.5 x 23.0 Normal 19.0 x 23.0 Close-up 26.0 x 23.0 Close-up 21.5 x 20.0 Normal reduced height 28.5 x 23.0 Normal reduced height 19.0 x 20.0 Close-up reduced height 26.0 x 20.0 Close-up reduced height
Note: Notice that the close-up mounts are narrower in aperture. This is of necessity because there is more material not common to both chips. However, close-up sizes are often used with normal distance subjects for masking purposes as are the reduced height sizes.
The Stereo Realist
popular 5 sprocket stereo cameras The Verascope Model F40
sprocket stereo camera
In Conclusion Readers kindly try and assimilate the contents of this piece. To be of any value, you will need to apply the suggestions while actually mounting up a number of stereo pairs into card mounts. Don’t hesitate to contact the author
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Just behind the window Too far behind the window Through the window !!!
Mounting Stereo Slides Part 2
by Ray Moxom