P3D Re: tintype stereoviews

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Mon, 2 Feb 1998 18:29:09 -0700
>From: John Saddy <john.saddy.3d@xxxxxxxxxxxx>
>Subject: P3D tintype stereoviews

>I apologise in advance if I am repeating what has already been covered, but
>I've handled some stereo tintypes in my auctions, and I know a bit about them.

Please forgive my almost complete ignorance on the subject of tintypes.
I don't think I've ever seen a tintype - I saw images in the recent Matthew
Brady exhibit in Washington, D.C., which I believe were daguerrotypes. My
understanding was that these images were one-of-a-kind - in other words, the
original exposure was on the final metal plate, and the only way to get
multiple copies was to take multiple photographs. Is this also true of
tintypes? The existence of cameras having four lenses would seem to support
that probability, since there would be less incentive to produce four
*negatives*.

>If the stereo pair is in one piece, and the images are pseudoscopic, that
>indicates it to be what I call an 'accidental' stereo. The dimensionality of
>these accidental stereos, when they are separated and placed in proper
>position, is weaker than what we usually see in a stereo image, as the
>lenses are closer together on those kind of cameras than a stereo camera.

You could also consider the pseudoscopic images to be cross-mounted, since
they could be cross-viewed for proper stereo.

How wide are the individual tintypes? If (as I suspect) they are original
images and not enlargements, then if the width is 70mm or greater then the
interocular of the camera would have been at least as great as the interocular
of most humans, but if they are less than 70mm wide, then the stereo effect
would have been diminished.

>If, however, the images are on one piece of metal, and are in PROPER stereo
>viewing position, and with at least typical strength of dimensionality, then
>I would suspect it may well be an authentic stereo tintype, made for that
>purpose.

Do you mean *two* pieces of metal? (Cut apart and swapped side-to-side to
compensate for the inversion of the camera lenses.)

>There were also tintypes sold in tissue-view-like mounts, with two separate
>pieces of metal. These must be examined carefully, as there is the
>possibility of fakery, using an accidental pair and a tissue-view mount.

I've noticed in some of the old Holmes prints in Stereo World that minor
details are different in the two shots, indicating that they were taken
at different times.

John R


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