High speed photograph of secondary drop formation after the impact of a falling drop with a pool of water. The original drop contained red dye. After cratering, the surface collapsed to form a column of water. At the top of the column, water surface tension effects create a secondary drop. This can be seen to contain a very high proportion of red dye, so little mixing has taken place. The water column itself is beginning to collapse. Twelfth in a series of thirteen frames.