Using a camera adjacent to an incandescent lamp with a polarizing filter that is supplying light at a 45 degree incidence angle to the ferrofluid cell. Basically, using a bright lamp instead of a camera flash. If you look, you can see the image of the camera reflected in the background. On the other side of the ferrofluid cell is a single rotating magnet, profile view with a north and south poles adjacent to the cell. Only the magnet moves, everything else is fixed in place.