Two trays. One of them is on a rack on the edge of a bathtub, while the other is on the floor of the bathtub.

The water flows into the top one first, which has holes drilled in the side. The water drains out of the holes and down into the second, lower tray.

Prints start in the lower tray, and are transferred into the top tray 1/2 of the way through.

Matt