Lanci's Panoramic Drawing Device

Figure LPD.1 – Lanci's Panoramic Drawing Device ca. 1598
Source: Vignola, Giacomo and Ignazio Danti. Le Due Regole Della Prospettiva Pratica. Roma: Francesco Zannetti, 1611.

Figure LPD.2 – Surviving Example, ca. 1557
Note that it is missing its curved image-plate.   Source: Museo Galileo - Institute and Museum of the History of Science, Florence, Italy.

Panorama vs Perspective: This is a device for drawing 180° panoramas. It should be better known and its significance better appreciated. Perspective devices constrain the eye so that the draughts-person can draw the world from a fixed point of view and a fixed direction with a limited angle of view (typically no more than 60°). Lanci's device allows the head and eye to rotate around a point, giving a constantly changing direction of view. The geometry of the view changes through motion and time to produce a result that is incomensurable to linear perspective.

 

We will call it cylindrical curvilinear projection.

 

How It Was Used: You can see in Figure LPD.3 how the device worked. It has a sighting tube that pivots side-to-side and up-and-down (in figure LPD.1 it is an alidade labelled ET). Looking through this sight, the draughts-person locates and follows points and lines in the scene that they wish to depict. Below the sighting-tube is a stylus that tilts and pivots in parallel motion. This stylus marks out points and lines on a wide sheet of paper attached to the curved image-plate.

 

Design – the Stylus: The three versions depicted here all have slightly different designs. In the case of LPD.2 the stylus is capable of pricking a hole, but not drawing a line (unless it were scribing metal). This is the type that Giacomo Vignola describes: the draughts-person marks significant points with the stylus then connects the lines later with a pencil. This approach would be conducive to drawing in hybrid projection – a wide-angle, curvilinear projection with the curved lines straightened.

 

The draughtsman in figure LPD.3 appears to be drawing lines with the stylus rather than marking points. He has his thumb on the end of the plunger as though he were using it like a syringe – pressing it in to contact the paper and releasing it to move to a new position. That action would suggest that the pencil is retractable on a spring.

 

Were I to build one of these (as I hope to do eventually) I would have the plunger tensioned on a spring so that it held the pencil lightly to the paper. That would allow the user to draw continuous vertical lines while the pencil lead moved automatically in and out (which it needs to do as the top and bottom of a vertical line would be further away from the point of pivot than the middle of the line).

 

Design – the Synchronizing Mechanism: The angle of the the stylus must be synchronized with the sighting tube as the draughs-person points it at different positions in the scene. In the device in Figures LPD.2 and 3 the two are rigidly affixed to a frame which pivots from below the stylus.

 

The device in Figure LPD.1 is poorly drawn and is difficult to interpret for this reason. However, if you read Vignola's accompanying text it appears that the spindle is supposed to tilt at the pivot CB even though CB is incorrectly oriented in the diagram.^[xxx] When I first saw this diagram I thought that there must have been a connecting-rod between the sight and stylus parallel to the spindle. As the sight was lifted, the connecting-rod would draw up the stylus at the same time. That may be what Daniele Barbaro describes in his earlier account of Lanci's device; however, the Italian text is obscure and Barbaro supplies no diagram.^[xxx]

 

I do not like how in the designs depicted here the sight and stylus move in parallel arcs. I am not convinced that the geometry is correct and there is too much travel forward and back, both for the stylus and for the observer with their eye at the sight.

Importance of the Device

Figure LPD.3 – Lanci's Device in Use, ca. 1600
Source: G. Parigi (ca 1600), Taccuino di arte militare, ms. Washington, Library of Congress, Rosenwald Collection, c. 239r: Baldassarre Lanci's instrument.

Importance in the 16 and 17^th Centuries: Lanci's device is described in two significant treatises on perspective.^[xxx] There were at least three different variants of it (Figures LPD.1, 2 and 3) so it was not an obscure one-off like Kepler's rotating camera obscura. Both Lanci's and Kepler's devices point to an interest in cylindrical curvilinear projection in this period.

 

Cylindrical or Panoramic Exhibition: Vignola and Danti, like Abraham Bosse, and using the same proof, warn that cylindrical curvilinear projection produces distortions. However, the device itself points to the solution to this problem which is to exhibit the drawing not in the flat, but rather on a curved surface. If you mount the pivoting sight in the place occupied by the stylus and view the image through it – turning one's head to change the direction of view – the lines will be rectified and appear just as they do when viewing the scene. That is one solution that I have proposed for the viewing apparatus for Fabritius' View in Delft – the Panoramic Motion Device. The same principle, a cylindrical exhibition surface and observation from the centre of rotation, was widely used in the 19^th century after the success of Robert Barker's first panorama (i.e. the building to exhibit panoramas) in 1793.

 

Chorography, popularity, link to curvilinear

Images Made with the Device: There are likely drawings in archives somewhere that were made by one of these devices, but none so far have been so identified. If made by pricking significant points, these marks would remain as evidence of this origin.

 

One candidate is Fabritius's View in Delft. I have argued that Fabritius's work is a cylindrical curvilinear projection, which is what Lanci's device would produce. One of the curious features of Fabritius's painting is its small size – 20.9 cm × 35.7 cm. The diameter of the image-plate of Lanci's device in the Museo Galileo is 30 cm, so the image-plate would be about 47 cm in width. While that is close to the width of Fabrituis' painting, that work takes in only a 90° sweep. The 47 cm of Lanci's plate is a 180° sweep. So, if Fabritius used a Lanci-like device, it would have to have been much bigger – 45 cm in diameter. The device depicted in LPD.3 could easily have been that size.

 

Footnotes:

 

 

References: