Ultrasonic Cutting Technology in Cameo Making by: Anonymous
Good afternoon Anca
thank you for writing in. Unfortunately I cannot see the deep recesses in the cameo photo so I am unable to provide an opinion based on the freshly fallen snow clue found in the deep recesses of the 'carving'. However, you have brought up a very important point in the development of cameo carving. With the advent of new technology, an advanced new method of reproducing cameo can now be obtained using an ultrasonic cutting technique. The question you are asking is a good one.
How do we distinguish between the hand carved cameo that is more rare and valuable and the new ultrasonically cut method?
One method of detection according to the Gemologist, P. Read is to inspect the cameo closely on the surface of the cameo. A "frosted" appearance can be seen in the deep recesses of any cameo that has been produced using this ultrasonic cut technique.
The use of the ultrasonic cutting technology is widespread in the food and textile industry too (woven or non-woven textile used in medical, technical, insulating, portable… fields). It brings together several steps of the traditional manufacture method: cutting, pricking, seaming, assembling, welding, cauterization... The use of ultrasounds has brought an increased quality of the final products, a higher productivity and unrivalled level of repeatability. The cuts and the welds are spotless, streakless, and with perfect cauterization.
Interestingly, the actual tool never touches the material itself. If you would like to see how the traces of freshly fallen snow are caused in the ultrasonic cameo cutting technique, there is a very short movie that clearly details this effect in the following link:
http://www.sonicmill.com/ultrasonic.html
Another clue is to examine the back of the cameo - the finding on the back will give dating clues. If the hardware predates the technology then the cameo is most likely carved by hand.
