The Forest Gate - watercolour, 16 x 26 cm
Rainbows are very difficult to paint convincingly in watercolour. As so often, the more you try to make them look 'right', the more they look false. The way to approach them, I think, is to just suggest them with a few colours; maybe red, yellow, and green, and put them in while the sky is still wet. This takes experience and confidence, but it's far more convincing than leaving a band of white paper, and then filling it in later. It's best not to make it a complete arc either: rainbows often disappear towards their ends, and this makes them look airy and fleeting. The painting has a double rainbow, but I have made the second one barely visible.