Alethoscope Genus (1861 - 1880?)

Figure AP-95-1613.1 –Megalethoscope
Source: Cinématèque française

Figure MCS-1.2 – Paper Diorama
Carlo Ponti, ca. 1870. Venise, quai des Esclavons et place Saint-Marc Gif animation © Rod Bantjes.

Carlo Ponti (ca.1823 - 1893) designed the Alethoscope (1861)^[1] and related Megalethoscope to be the unequalled perfection of the optical machine. These are large-scale viewers for photographic paper dioramas.

 

The defining features of the genus are:

	• a rotating body to change between "landscape" and "portrait" orientation of prints;
	• two mirrored front-flaps, the choice of which depends upon the orientation of the print;
	• a viewing-hood to minimize glare on the lens;
	• a large squared lens in a movable carriage adjustable by brass side-knobs;
	• internal masking to eliminate all distractions from the internal illusion.

 

The Alethoscope is the second of four early devices, including Adolphe Beau's Neomonoscope(1860), Charles John Rowsell's Graphoscope (1864) and Francis Frith's Cosmoscope, (ca. 1870) to apply the 18^th-century biconvex lens to the photograph.

 

Here I identify three species of Alethoscope. There is at least one more: the Ponti Alethoscope that has a curved image-plate unlike the Naya version that has a flat plate.

Ponti Megalethoscope:
	AP-95-1613

The Megalethoscope (62 x 48 x 90 cm) is similar in size to the Alethoscope (62 x 46 x 90). It takes the same sized images, plus a number of smaller formats. Alternate image-frames, including one for the popular carte de visite format, is touted as one of the improvements over the original Alethoscope, although the min-Alethoscope has this capacity as well.

 

The other improvements that Ponti claims for the Megalethoscope are either minor – a double lens that can be cleaned – or to be taken with a grain of salt: "the enlargement of the images is significantly increased, the relief more developed, but without exaggeration; defects of sphericity or refractivity are minimized; the clarity is greater, and the range of views is framed in such a way as to prevent the eye from wandering over the margins at the expense of the stereoscopic effect."^[2]

Naya Alethoscope:
	MCS-1

The Naya Alethoscope embodies most of the improvements of Ponti's Megalethoscope, but is unique in having a flat, rather than a curved image-plate.

 

Mini-Alethoscope:
	MNC-M02003

At 47.3 cm in length, this device is about half the size of the Megalethoscope (90 cm). Like the Megalethoscope, it can accept different sizes of images, the largest of which is curved and 17 cm wide. That is less than half the width of the Alethoscope image-plate (36 cm).

 

Endnotes: