P3D Re Chimenti "stereoscopic drawings"

[abram klooswyk <abram.klooswyk@xxxxxx>]

Dale Walsh wrote (P3d 3358, 19 Jun 1999):
>As an unrelated question, has anyone any sources of
>information on the 16th century Florentine painter 
>Jacopo Chimenti who did stereoscopic drawings?

The short answer is: he didn't.

Longer:
When talking about Sir David Brewster, never forget that he
did numerous stereoscopic inventions and that he brought
stereophotography to France and to the Crystal Palace,
starting the great public interest in stereoscopy.
However, on the other hand he is the source of several more
or less serious errors and fallacies in (the history of)
stereoscopy, a notorious one being the Chimenti "stereoscopic
drawings".
A detailed discussion of this fallacy is in:
     Nicolas J. Wade: "Brewster and Wheatstone on Vision",
     Academic Press, London, New York etc. 1983.
This book contains almost everything which both scientists 
wrote on binocular vision and stereoscopy (except Brewster's 
book "On the Stereoscope"), with a critical assessment by Wade, 
who is an authority on the subject.

On the Chimenti drawings it deals on page 46-49 and 183-192.
In short, Chimenti made a drawing of a man from two slightly 
different viewpoints (and on a slightly different scale). 
The small differences give rise to accidental local depth effects, 
when you fuse the pair binocularly. 
Brewster however said that the stereo effects were intentionally,
which challenged Charles Wheatstone's priority. The debate rose 
high, but was already settled in the 19th century. 

The great von Helmholtz said: ... it seems to me very unlikely
that Chimenti intended them [the drawings] for a stereoscopic 
experiment, because the stool, the dividers, and the plumb line,
which could easily have been drawn correctly, are treated as 
unessentials and all drawn so irregularly and so differently that
they cannot be combined [stereoscopically]. (...)
It seems more probable to me that the artist was not satisfied 
with the first figure and did it over again (...).  (1866).

Brewster's fallacy has been repeated over and over again, till
now, on P3D....

In PHOTO-3D Digest 3032, 20 Oct 1998, in a posting called 
"From Euclid to Wheatstone and further on", I have argued that:
"The stereoscope could not have been invented before the 
stethoscope." (The latter was invented in 1812).
In PHOTO-3D Digest 3035 I have added: (...) "making two 
perspective projections and fusing them was not *conceivable* 
before the 18th century." 

By the way, Dale Wash has an interesting site with many stereo-
images (http://welcome.to/solidillusions), but it features 
another of Brewster's fallacies:
"The principles behind stereoscopic imagery were developed by 
Euclid in ancient Greece."
I have discussed Euclid's "binocular" theorems in TECH-3D 
Digests 366 and 367, 26 Sep 1998, in postings on "From Euclid 
to Wheatstone". Euclid didn't say anything on depth perception
or stereoscopic imaging.

Abram Klooswyk


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

End of PHOTO-3D Digest 3360
***************************