Grey Skies

I've drawn the wood, meadow and ponies from my studio window so many times that this afternoon at 5, when I finally get a chance to draw, I decide to make some quick sketches of the banks of low grey nimbostratus that are parading along over the wood from north to south.

Although some of the clouds have definite edges, their forms aren't picked out strongly by sidelighting on this overcast afternoon so it's all rather amorphous.

• I paint a light background wash of warm and cooler greys

• when that's dry, brush clear water over it

• using a smaller brush, I paint the darker greys of individual clouds so that they have soft edges where they bleed into the background

5.45 p.m.

After those two half-page sketches, I take a full page of my 6 x 6 inch sketchbook to include a bigger area of sky. This gets too wet - it dribbles down over the horizon line that I'd just painted.

For all of these watercolours I kept my sketchbook propped up at a slight angle so that I could paint the washes starting at the top and working to the bottom. That way the bottom edge of the wash stays wet. A bit too wet in this case.

Here's my final sketch, painted as the light, and what colour there was in the sky, faded.

Yellow Ochre v. Raw Sienna

Greys skies: rather than reach for the Paynes Grey or add water to one of the blacks (as I did in my school days) I prefer to mix my own greys, putting together a variety of blues with browns, reds (such as alizarin crimson and permanent rose) and earth yellows.

With so many greys in the sky this sounds bewildering but I find that if I take my best guess when I mix the grey, when I start painting I soon realise that I need just a spot more blue, or yellow etc.

Cerulean Blue, a 'sky blue' - azure - very slightly turquoise, isn't a 'must have' colour and I don't carry it in my smaller paintbox but it is useful to have for subjects like this. For years I've gone for a very limited range of colours but I feel I might start working with a larger range again.

Yellow ochre and raw sienna are all but identical in colour but I'm beginning to go over to raw sienna from the yellow ochre that I've always carried in my box. Raw sienna is more transparent in a wash than yellow ochre and I think it is easier to get a smooth wash with it.

I painted the two swatches by mixing each colour, applying a brushstroke on the left then adding more water to the pool of colour on my palette and continuing the swatch to the left, finally adding more water so that with the third brushstroke the colour fades off to the right.