Hertz is a series of photograms capturing an oscillating wave patterns in water on an E6 4×5 transparency film with white polarised light. The name refers to Heart in German as well as to the unit denomination used for a frequency equal to one second per cycle.
For this a sound frequency is send through an amplifier to let water resonate in a petry dish to be modulated by a sine wave generator via a transducer to a vibration plate. This analogue technique requires a completely darkened room and is hence performed in a very intuitive process to immortalise a split second of an unseen wave pattern.