The Photoliptophone

Gallery opened 19 May 2018 Updated: 6 Apr 2022 New pic of reading head added

Distributing audio on paper

The Photoliptophone (or Fotoliptofono) was a method of printing sound on paper, for reproduction by a photocell. It was an example of optical recording, like the Duotrac system which used photographic recording on plastic tape. A complete article on the system is reproduced here; it is largely self-explanatory. 'Fotoliptofono' seems to have been the original name of the system, but it was more often called the 'Photoliptophone'.

The system was introduced by Argentinean inventor Fernando Crudo, who took out a patent in 1930.

Left: The article on the Fotoliptophone in Newnes Popular Mechanic: 1936 The distinguishing feature of the Fotoliptofono from other optical/paper systems was the way it used a flat sheet of paper (presumably the audio track was in the form of a spiral) rather than a long paper tape. It would appear that the two edges of the paper would have to be aligned very accurately indeed when it was being wrapped around the cylinder, if repeated audio glitches were to be avoided. The advantage of the format is that a simple sheet of paper could be printed very quickly and cheaply, while printing long paper tapes would have been difficult and expensive, requiring specialised machinery. The article is regrettably short on technical detail; I would like to know how fast the audio track moved past the photocell. The lower photograph suggests that variable-width optical recording was used, variable-density being impractical with a printing process. It is suggested that the Fotoliptofono had a frequency response of 16 Hz - 7 kHz, which would have been very respectable for its day. The lower limit is set by the electronics as the recording process could go down to DC. As playback was optical there was no wear on the recording. Source: Newnes Practical Mechanics Jan 1936

Left: The Photoliptophone drum: 1930 The cylinder was 16cm in diameter and rotated at 85rpm. The sheets were 50 cm x 40 cm, apparently the size of existing X-ray film. Each sheet could carry up to 330 tracks, each 1.5 mm wide. Playing duration was about 4 minutes. Recording was done by wrapping the X-ray film around the drum and exposing the film with an audio amplifier connected to an oscillograph.

The Photoliptophone was briefly described in Popular Mechanics for Apr 1934

Left: The audio tracks on a Photoliptophone sheet During the 1930’s, efforts were made to patent and exploit the invention in no less than 31 countries, but with no commercial success. The short playing time was a disadvantage.

Left: Photoliptophone drum The label affixed just below the reading head says 'Fotoliptofono- Argentina 1940'. Note that this is not the same Photoliptophone as in the picture above; the reading head is different.

Left: Photoliptophone drum Looking at the drum from the other end. Note chain drives for traversing the reading head.

Left: Photoliptophone reading head It is not wholly clear what is here but it looks as though there is an illuminating lamp at the upper right and a microscope objective at middle right. The shiny tubular thing in the middle is probably the photocell. Presumably a light-tight cover has been removed. This does not seem to correspond with either of the two Photoliptophones pictured above.

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