Re: Viewer lighting

["The Photo-3D List" <photo-3d@xxxxxxxxxxxxxxx>]

>Date:   Wed, 27 Mar 1996 09:15:04 -0600
>From:  Greg Erker  wrote:

>
>  I also build an add-on box with a battery powered light. It
>uses 2 C-cells and one of George's frosted halogen bulbs
>(0.8A at 2.5V).  It works reasonably well except for two
>things (three if you count the weight).
>
>  The first is that the illumination is not totally even. The
>bulb is centered from side to side, about 1/2" behind the
>diffuser and slightly below center vertically. I have a white
>reflector behind the bulb in an arc (sort of like my Red
>Button). The top and the bottom surfaces are also white. Still
>the left of the left eye is brighter than the left of the right


I modified an Iloca 35mm stereo viewer many years ago. I used a scheme
similar to your own - behind the slide I placed a white plastic diffuser
screen ("perspex" is the trade-name in Australia). Then behind that I
placed two lamps. Each lamp was on-center with the apertures in the slide.
I wasn't relying on any reflector at all - mainly just the direct light
from each lamp - in fact I believe there was no room in the viewer for a
reflector after I had modified it. But I did make sure that the all the
surfaces surrounding the lamp were white - but there was no actual
reflector. I found the light to be quite even. It's been a long while since
I used this viewer so I can't give a much better description of its
performance than that.

As an aside, this was before suitable halogen lamps became available. So I
used two 6V/3watt (approx) lamps (with a textured glass surface to improve
diffusion a bit), an external power supply, and a colour correction filter
to push the colour temperature of the lamp up (from around 2800 or so to
about 3300 or so). These are blue filter "gels" like those often used on
lighting sets for video/film. Its cheap stuff and comes by the meter. I
recall that the metal case of the viewer got quite warm if operated for a
while.

Steve Spicer






------------------------------