The History of the Anaglyptograph

An anaglyptograph is an ingenious nineteenth century instrument comprising a gramophone-like needle that traces the surface of a three dimensional object and, by its particular construction, converts the relief movement of the needle (input) into a horizontal deviation proportional to the relief height of the object (output). Crucially, by attaching an engraving tool to the output, and placing a blank plate under that, the anaglyptograph would engrave a copy of the three dimensional object. Prints could be taken from the engraved plate and published in a books.

In the earliest times, a technician would painstakingly trace the needle across the object hundreds of times, each at a different offset. In later systems, a mechanical arrangement replaced the human technician and enabled automatic tracing.

Higher quality could be achieved by spacing tracing lines more densely, but it was also possible to synthesize a directional light source: by choosing the azimuthal angle of the tracing lines and the elevation angle of the needle, the engraving would have the sparsest lines (and lightest apparent shade) for relief ascents at a selected angle and the densest lines (and darkest apparent shade) opposite that orientation.

The history of the anaglyptograph is well told in [Stannard1859] and by Dick Johnson in [Johnson2017]. Gobrecht, an associate of Jacob Perkins and living in Philadelphia, was first to publically report his construction of a crude device, in 1817. Asa Spencer, an American artist and banknote engraver, built one or more machines based on Gobrecht’s design, and took one to London in 1819. A gentleman there purchased the machine, and, upon the gentleman’s death, it passed to John Bate, Optician to the Admiralty. In Stannard’s telling, Gobrecht’s design was crude in several senses but aesthetically the most important was that the device would create a distorted tracing of the relief, where the greater the depth of the relief, the greater the distortion. Bate’s goal was to reduce or lessen this distortion, and indeed he “succeeded in effecting an alteration in the principle of the machine, by which the distortion was wholly removed, the change being a very ingenious application of a mathematical relationship between certain lines.” In 1832, Bates received a British patent, Machinery to Produce Imitations of Medals, Sculpture, &c., number 6254, for his design.

In Johnson’s telling, the more important personage was Achille Collas, a French mechanic, who independently re-invented the same device and produced his first successful engraving 1831. A French businessman Nolte acquired the rights and persuaded a publisher of encyclopedias, Lachevardiere, to join the venture as a manager. Their company went on to publish 20 volumes of medals, coins, seals and small bas-reliefs over 24 years.

Regardless, it is Bate who carefully documented his machine by way of his patent, and to which posterity is most grateful.

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Using the spelling of his era, Bate describes its operation thus: “Figure 1, represents a side elevation of my improvement on machinery applicable to the imitation of medals, sculpture, and other works of art executed in relief. A-A represents a fragment of a board or table, and B shews a vertical section of a brass socket fixed thereto. C is a square brass standard made to slide up and down within the socket, being very accurately fitted. D is a steel screw, having a micrometer attached at its lower end, by which means it can be turned so as to move the standard C at equal distances, either ascending or descending. E shews a plate of metal fixed to the standard C, and inclined to the horizontal plane of the table or board A-A, at an angle of forty-five degrees. The upper edge of this plate has a groove formed in it to receive two bevelled rollers of a carriage, now to be described. F represents a carriage, which moves very freely on the plate E by means of three rollers, two of which are bevelled so as to enter the groove formed to receive them or the upper edge of the plate E. In this view only one of the bevelled rollers a can be seen, the other being immediately behind it. These rollers are made with long axes, and very accurately fitted in their bearings, so as to move freely without shake. The lower part of this carriage is supported and moves on a single roller, b, the axis of which is placed at right angles to those already described, the periphery revolving and resting upon the ledge c. d-d represents a sliding plate, which is made very true and parallel on two of its edges, and these are bevelled on each side so as to produce a double prism. The champhered edges so formed enter the grooves of four rollers fixed in the carriage F; two of these rollers are seen near e-e; the other two, being placed immediately behind, cannot be seen in this Figure. By these means the sliding plate d-d, is made to move very freely, and yet with great accuracy. f represents a point fixed to the sliding plate d-d; this is used to trace over any medal or any other suitable work of art that is required to be copied; G shews a section of a portion of a sphere rising from a plane surface, and similar to a medal in its general form. Any such subject may be fixed to the supporting frame H by any suitable cement, care being taken that its plane be placed in a proper position. I is a metal guide fixed at its lower end to the sliding plate d-d; the upper portion of this is formed into a straight edge at g and stands perpendicular to A-A. K represents a vibrating lever, the arms of which are equal; this swings freely on two conical points, one of which is seen in the arm L fixed upon the carriage F. The upper end of the vibrating lover has a friction roller L placed in it, which is always kept in contact with the straight edge of the guide g, by the spring i, while the lower end of the lever moves the frame M, at the end of which the diamond point is fixed, as shewn at j, perpendicular to the surface of the copper plate N, which lies parallel with A-A. The left-hand end of the point frame M is jointed on each side to the lower end of the vibrating lever K, forming an elbow joint therewith, the pivot- or bearings being made conical, so as to avoid friction as much as possible. p represents a small barrel fixed on an axis, one end of which turns in the end of the arm q, and is retained in any position by friction. The other end has a flat button formed on it by which it may be turned. r shews a small silk cord; one end of this is coiled round the barrel p, and the other is attached to the point frame M. By these means the diamond point may be raised from the plate and kept suspended at pleasure. 0 represents a metal plate fixed to the bracket p, which is firmly attached to the inclined plate Z. There are two such brackets, one is supposed to be removed, to shew the parts that would otherwise be hidden. Q, represents the plate carriage, which has three friction rollers placed in frames under it. Two of these rollers are bevelled and run in a groove formed in a plate 0; the other roller is plain, and rolls on the surface of tho same metal plate. k is a steel chain, one end attached to the arm B and the other, at t, to a stud projecting from the under side of the plate carriage Q. m shews a cord made fast at one end to the stud near I, and passing over the pulley n, it hangs down and has the weight 0 appended to it, by which means the carriage will be drawn along in the direction of the dart, whenever C is lowered by the micrometer screw D. When this machine is to be used, the micrometer screw D should be placed in the centre of its range, as shewn at D in Figure 1, and then the medal or other object to be traced over must be placed at such a height that the tracing point f may be brought just in contact with the centre of the medal or other object. When the sliding plate d-d, is placed in the centre of the limits or range that it has to move in between the rollers that confine it, the centre of the copper plate N must at the same time be placed immediately under the diamond point with its edges parallel to the plate Q, . The machine and plate being thus adjusted, the micrometer screw D must be made to raise the standard C, and all tho parts combined therewith, until the tracing point f will nearly reach the top of the medal or other subject G, at s The tracing point must then be laid hold of by the hand, and brought into contact with the surface at s (moving the screw D as may be required, to bring the tracing plate d-d, into its mean position) by means of the combined motions of d-d, and F. The machine will then be in the proper position for beginning the first line, when the button t must be turned, and the diamond point gently let down upon the copper plate, and the tracing point f being then passed very carefully over that part of the medal which presents itself to it, the diamond point will then be found to have etched a line on the copper plate exactly corresponding to the undulations which the tracing point has passed over on the medal. The diamond point must then be raised from the plate, and the micrometer screw must be turned so as to produce such a space between the lines on the copper plate as may have been previously determined upon, and the same movements repeated, until the whole surface of the metal has been traced over. When sculpture and other works of art are to be traced over, and the undulations of the tracer transmitted to a plate so as to produce a copy thereof, such works must be placed before the tracer f, in vertical position, and the mode of setting and adjusting the machine, and also the copper plate, must be adopted as before described, and then if the tracer f bec made to pass over every part that the tracing point will reach, such undulations will be transmitted to the copper plate, and a correct representation will be the result. In some works that are executed in very high relief, it would be quite impossible to reach many parts that are in deep recesses with a point of the ordinary conical form, but for such purposes I have invented the following instrument, which I call a tracing blade.”

The tracing blade is shown in Figure 2. Figure 3 presents a front view of Figure 1.