P3D Part 2: Ways to mask an RBT mount with currently availablematerials

[Jon Golden / 3D Concepts <3dman@xxxxxxxxxxx>]

Making easy custom masks for RBT masks: Take aluminum masks, EMDEs work best because they are thin, Old Realist or ALbion are also useful but not as thin.   I use the Euro 7 EMDE mask for reducing the height of an RBT 5 Realist...since the top or bottom edge of the EURO EMDE can extend beyone the aperture of the RBT.    If I need to mask by reducing height of larger than and RBT 5 Relaist  (RBT &, WIDE or FULL) ....I use the entire outer long edge of any EMDE. Cut the EMDE to fit horizontally  between the snap pegs of an RBT, then using Reel 3D adhesive tabs (Cat # 8020) set the mask in place and tab down.  To make sure the mask is aligned to the stereo window ....you may have to check it in a projector (this is the hard and laborious way) ...or use an active mounting system like a SAM (3D Concepts)  or one of Ron Labbe's (Studio 3D) stereo headset mounters clamp shut with the white half.  
The slide looks great, projects well, I do it for tough close-ups...a great benefit!!  I found this out by accident when I wanted to project a hyper-stereo Paul Wing gave me.  He custom masked the image using an aluminum mask.  Problem was, my show was in RBT's, and mixing formats when projecting is not good, due to the different centers between stereo mounts.  Paul created a custom mask by taking a 7-sprocket aluminum mask and closing down the vertical by almost 25%.  I tried re-mounting to a standard RBT-7, but the emulsions had too much vertical offset, so I created my own custom mask to allow more vertical "play" for alignment.   I took an aluminum mask, using scissors, I trimmed the mask's top outer edge, to make it sit snug between the snap pegs, and clamped the mount shut.  Paul Wing was impressed when I showed him, and he's  a tough guy to please (The legendary Cranky Yankee has earned his title!)  Make your own custom masks, once you get the hang of it, it's easy. 

I have a  slide that I created to show at NSA/ISU Atlanta 1995 that shows this technique...and in fact the film chips can slide back and forth under the modified  EMDE mask...so I can set the window independently of the mask.  This slide was shown at all NSA's including this years Green Bay event.  I projected it at Dr T's Slide mounting workshop, toards the end of the session,  to demosntrate the setting of the stereo window as some of you may recall.   An image of the nosecone of a C3 transport plane was the subject at hand....and I moved the chips closer and closer together...with help by the EMDE mask at the bottom of the image...to obscure foreground objects that were too close to allow the nose cone of the plane to come through the stereo window.  I have opened and closed that RBT mount...I am sure...at least 200 times, and have projected it all too many times as well...and two of the locking pins finally fell off at NSA this year!  It served its time well!

Opening and closing RBT mounts with ease...thats another subject .  If anyone wants that posting...just say the word.

Regar-D-D-D-s
Jon G