Exposure and viewer illumination

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

I basically agree with what Robert Linnstaedt wrote about exposure and
viewers:

>Slide film is more tolerable when slightly under-exposed.
>But, if over-exposed, the diapositive lacks _density_ and nothing 
>you do will change that.
>Less light only makes an over-exposed slide look better in the same 
>way that candle-light makes us look handsomer. 

This issue is related to the use of variable light intensity in stereo
viewers, like the Kodaslide II, Realist green button, etc.  If the slide is
overexposed, turning the light down does not help much especially since the
light temperature goes down, resulting in a muddy orange light.  If the
slide is underexposed, turning the light up helps a little but usually the
viewer is used with light intensity at high so there is no place to go
higher! (It is my observation that most owners of Kodaslide II and Realist
green button viewers, use their viewers at maximum intensity most of the
times which is a reasonable practice for dimmer non-DrTized viewers ;))

I think that the best use of variable light intensity in viewers is mainly
to match the ambient light.  Light intensity that looks OK at home in the
evening will look too dark in a brightly lit environment (office, daylight,
etc.)  Slides need plenty of bright light to look at their best.   Light
intensity that looks OK in daylight will look too bright in a dark room.

For those who run their viewers in batteries, it helps to have one bright
and one dimmer light bulb.  In a normal/bright environment, use the bright
bulb.  In a dark room use the dim bulb.  I was in a wedding reception in a
room with very low illumination and the halogen bulb in my red button
almost hurt the eyes!  If that happens again I'll make sure I put a dimmer
bulb in the viewer. If I am not sure, I'll carry both bulbs.  That's called
"poor man's light intensity control" ;)  Of course, there is the "even
poorer man's control" which is based on changing the distance of the $3
viewer from the 100W household bulb!!! ;) ;) ;) (apologies to $3 viewer
users!)

George Themelis


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