Re: RBT mounts... - alignment

[P3D Dr. George A. Themelis <fj834@xxxxxxxxxxxxxxxxxxxxx>]

>> I have a question:  Do you need a projector to see if your slides are
>> properly aligned?  Isn't the viewer good enough?  
>
>Definitely not. Wildly misaligned slides can be quite acceptable
>in a viewer, but still twist one's eyes off when projected.  

The question is not if errors are acceptable, but if you can see them or
not.  I can detect aligment errors in the viewer.  If the top or bottom
edges of the mount do not cut the picture at the same location then the
chips are misalinged.  If one side is higher all across the length then you
have vertical misalignment.  If one side is higher in one side and lower in
the other then you have rotational misalignment.  If one chip appears
aligned at the bottom side but not aligned at the top side then you have a
difference in size (due to FL mismatch most probably).  

The only problem is detecting alignment in the viewer is when there is
nothing at the egdes to define your cut (as in featureless sky).  You can
then slide an aluminum mount down in front of your slide and check any
point in-between top and bottom.  Charles Piper gives some details on that.

>I've also 
>found that sometimes I've ended up with people with their waists cut off
>when projecting -- but looked fine in a viewer (A Themelized one
>no less).  I say this from experience..... :-(

That means that you cannot appreciate the location of the stereo window in
the viewer as well as in projection.  It is easier in projection but still
I can see it in the viewer (a Themelized, of course!)

>However, one still needs to check with a projector to judge
>"exposure" -- unless one has a dimmed and "calibrated" projection-
>simulation viewer.  Ones that look great in a viewer sometimes are
>real disappointing when projected.  I speak from experience
>again.  :-(

No doubt that projection (at the intended projection conditions) is the 
final judge, but a lot can be seen and done with the simple viewer.

-- George Themelis


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