P3D Re: HP Scanner Adapter

[Jonathan Gross <jonathan.gross@xxxxxxxxxxxx>]

Jeff Jessee wrote:
> P.S. The adapter is a 45-45-90 plastic triangle with crude
> mirrors (metal)
> on each side of the right angle. (As I imagine everyone
> guessed from
> the picture)

I applaud Jeff for experimenting with the HP scanner adapter, but I
think that his statements both under estimate the deceptivly elegant
engineering, and perhaps over state expectations for the device.

The device is more sophisticated than it looks. Although it appears to
be a simple "45-45-90 plactic" pyramid with crude mirrors, the patent on
this device is 36 pages long!  A careful inspection will reveal that it
is not completely symetric, which accounts for the registration arrow on
one corner of the pyramid which is designed to fit ito the upper right
corner of the scanner. Although the unit will work when not aligned into
the corner of the scanner, accurate registration is important because
the mirrors are not square to the surface of the scanner; they are
designed to compensate for the distance between the lamp and the
sensor.  This is the origin of my previous comment:

> HP claims to only support it for the 6000 series, but I used
> it successfully with an HP4C.  I do not know why it would not work with
> non-HP scanners, as long as the lamp and sensor are in roughly the same
> relationship to each other as on the 6100C.

Originally I was confused by the choice of brushed aluminum for mirrors,
but then I began to suspect that they might diffuse the light for more
even lighting.  Replacing them with "better" mirrors might not yield
better results.

Finally, unless the OPTICAL resolution of the scanner is very high
(1200DPI), the resulting images may be suitable only for visual
identification in a cateloging application. As stated in my original
posting:

>  Although this limits the
> resolution of the scan to the optical resolution of the flatbed flatbed
> scanner used, the resolution may be adequate for the 2D imaging of
> slides for cataloging, etc.

The adapter is a great value for $5.50, but there still is a reason that
high quality film scanners (2700DPI, 36-bits, 40 sec. scan time) cost
well over $1500.  To find out more about high quality scanning of stereo
slides, visit

http://www.frostbit.com/Catalyst/stereoscopic.html#services

and follow the link "scanned"
(http://www.frostbit.com/Catalyst/scanner.htm)

Jon Gross


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