Ultrasonic tanning and dyeing

Ultrasonic tanning and dyeing experiments are reviewed. The similarities and dissimilarities of both processes are discussed in the light of the physico-chemical processes involved. The increase in ultrasonic power required for large-scale industrial employment is estimated. Since these power requirements cannot be met by crystal transducers, it is suggested that the operating frequency be reduced to the higher sonic or low ultrasonic range in order to permit the use of magnetostrictive devices. The relative effectiveness of sound at high and low frequencies is discussed. Some sources of high ultrasonic power are described.