As shown in the photo and diagram, a stoppered reservoir is supplied with an air inlet and a siphon. The pressure at the bottom of the air inlet is always the same as the pressure outside the reservoir, i.e. the atmospheric pressure. If it were greater, air would not enter. If the entrance to the siphon is at the same depth, then it will always supply the water at atmospheric pressure and will deliver a flow under constant head height, regardless of the changing water level within the reservoir.
Nearing completion with water tray at base, diffusion screen for flash units behind the construction; and the electrical connections set up and ready to go.
The 3 water drops can be programmed as to flow timing etc whilst the drop geometry can be physically adjusted manually. The flow controllers are electrically adjusted by a program running on a central controller (StopShop Studio) which has 6 channels available. The first 3 channels are the drop controllers, then 2 flash units behind the diffusion screen and the camera shutter controller which is activated from the program.
Construction continues and I have added the 3 syphon tubes with Mariotte bottles (Mariotte’s bottle is a device that delivers a constant rate of flow from closed bottles or tanks.) to the top of the stand and also added the 3 water valve mounting brackets. The water valves were added and set up to be able to be adjusted as required for drop geometry. A mini drop sensor is used to trigger the capture process once the water drop falls past the opening.
I have always been interested in all aspects of macro photography – and water drop photography has had its own appeal for many years. Like most photographers, I tried the hit and miss approach with mixed success for single drops of coloured water, milk and chemical solutions of various hydrophilic and hydrophobic additives. Whilst those results satisfied my inner photographer at a basic level, my scientific background craved a more logical and analytical approach – hence this project!