Cream food colouring and water.
Preparation
Fill a tank of water approx three quarter full, let settle and try to remove any air bubbles. Mix food colouring with single cream (double cream was too thick) using a syringe or dropper take up some of the mixed cream.
Place camera on a tripod with remote release attached, using manual setting set camera to take a photograph of the tank that comes out black try iso 200, shutter 1/160 sec and F16 as a starting point.
Lighting
You now need to add lighting to the set up to illuminate the drops falling into the water. I used a speed light at one side of the tank and a small table top light (continuous light) on the other side, you could use another speed light. link the speed light to the camera with a transmitter and receiver, the speed light will illuminate the drops as they fall when you take the photograph, the other light set a little dimmer, or moved away from the tank will help to balance light on the subject.
Focus point
Place a ruler or stick etc in the water in the centre of the tank, use manual focus to get as sharp an image as you can on the ruler, lock focus and remove the ruler, The position where the ruler was is where you will drop the droplets in to the water.
Technique
Drop one or two drops into the water wait until they have sunk an inch or two and have started to take a shape, fire the shutter release and take a photograph. If you place the syringe into the water and force the cream out you will get a cloud effect.
Post Production
I used photoshop to clean up the images removing any bubbles that I missed and processed the image looking at the colours, do they need a boost? can I add another shape from another image to this image ? I used the cut and paste method, select the shape, copy and paste in to your image and set the layer to lighten or screen, you can then use edit and transform to move the new part of the image around to achieve a more pleasing image.
The downside
be warned you will need to change the water often so it is better to do this near a water supply.
any questions just contact me, I would love to see what you produce.
set up
