Working in the fresh air can be one of the most pleasant aspects of watercolour painting, but in England it is not only a fair-weather activity. The morning I chose to start preliminary drawings of Warwick Castle was bright but bitter and, not for the first time, I contemplated still life and interiors as alternative subjects!

It was the first really fine day of the year, but I quickly realised that a great deal of my sketch would have to be in ‘shorthand’, to be finished in the warmth of the studio: architectural features repeated, lines straightened, shadows blocked in, then compared again with the castle itself.

The bright spring light picked out the edges of the architectural features in sharp relief, ideal for work of this type.  The topographical painters of the last century preferred the lighting effects created by a low sun because it showed three-dimensional form in clear detail against long dark shadows.  An afternoon sun is kinder; the dazzling winter light bleaches the middle tones, erasing the more superficial detail and creating dense shadows heavy with dampness and masking whatever is within them.