Heat.

Really strong light hitting off the radiator in the kitchen this morning - decided to try out yesterdays technique on the strong contrasts that resulted.

Had a problem with the multiply blending mode because it increased the contrast even further and over-exposed some of the highlights. After a bit of messing around and much lightening of areas of shadow using the dodge tool, I eventually came up with this.

Seemed appropriate as today, the plumber who installed the central heating last year came in to fix the stuff that the kitchen plumber hadn't - you know, little things like making sure that there was gas in a pipe that was to supply the hob and removing all the air from the heating system after installing the radiator...