Here is a photo of my plate warming set up. It consists of a slab of marble under which is a hot plate. The end is allowed to become warm to the hand and not very much warmer. The other end stays cold. A piece of glass is set on the warmer for as long as it takes to get a can of emulsion out of the water in the sink, not long. Plates are hand poured just to the left of the marble slab. The plate is set onto the warm end for a measured amount of time. Today I used 2 min.. The plate is then pushed back onto the cold part. The emulsion has a chance to level out, flatten, and perhaps rise in ISO.