'I imagine that, like me, many of you are members of the National Trust or regular visitors to National Trust sites,' says Tony Underhill.

'If you’re a regular visitor, you’re probably already conjuring up visions of historic buildings, beautiful gardens and quiet corners. Or perhaps you’re thinking of coastal walks, or boats sitting in the mud waiting for the tide to come in.

'All perfect sketching and painting subjects. Yet while I see plenty of people snapping away on cameras during my visits, I hardly ever see anyone else drawing or painting. Perhaps the idea just doesn’t occur to them. Or perhaps it’s the thought of painting outside or in public, or because it requires too much equipment or time.

'Well, you’re missing a great opportunity if you don’t paint during your visits. Drawing and painting outdoors in such beautiful and relaxed surroundings combine two great pleasures in the same visit, and on the rare occasions I’ve been approached by passers-by, they’ve always been friendly and supportive. So I hope you’ll be tempted to have a go this year. I’m sure you’ll enjoy it.'

Gothic Temple, Stowe Landscape Gardens, pen and watercolour, 7x10in. (18x25cm)

Keep it simple

Based on personal experience, I believe the key to success when painting National Trust properties on-site is to keep it simple in every respect: concept, equipment, subject matter and technique.

I find this formula not only produces the best results, but also leaves plenty of time for the day’s main activities: to view the house and grounds, go for a walk, and, of course, visit the café.

Bridge House, Ambleside, pen and watercolour, 7x10in. (18x25cm)

Concept

Don’t go out with the idea of producing a masterpiece. Instead, I suggest your aim should be to produce a quick, easy, personal record of the day. Even a two or three minute ‘enjoyment sketch’ can be fun and great practice in observation and drawing skills (see my pen sketches, above right).

If a subject really takes your fancy, you can always use your sketch to produce a larger or more detailed piece of work at home, particularly if you take some support photographs as well.

Gateway to Walled Garden,Oxburgh Hall, pen and watercolour, 7x10in. (18x25cm)

Travel light

The equipment I use on-site is minimal and easily portable:

• 7x10in. watercolour Sketchbook
• Waterproof drawing pen
• No. 6 travel brush
• Small field box of watercolour paints with integral water bottle.

I use a suitably placed bench or wall to sit on, or lean against a tree – any of which makes me pretty invisible to passers-by.

So unless drawing or painting is your sole aim for the day, leave the easel, paintbox, brush rolls and artist’s stool at home; they’ll only slow you down on your day out and attract unwanted attention.

Subject matter

Don’t rush to the main house. No matter how tempting they look, National Trust houses are often ornate with lots of chimneys, dormer windows and projecting bays. Wander around first and find one or two simpler, more easily achievable subjects. If the house has been there 500 years, the chances are it will still be there a few hours later!

Something suitable always catches my eye; perhaps a dovecote in the walled garden or a gateway (right). If you do tackle the main house, do so from a viewpoint and distance that simplifies the subject matter as much as possible without spoiling its attraction.

Demonstration: Brancaster Staithe

When I look back at the sketches I included earlier they remind me of enjoyable days out, some wonderful National Trust sites and happy times spent drawing and painting. So the sketches achieved their intended purpose.

More often than not, I’m happy to leave it at that. But every now and then one of them inspires a larger studio piece or, with the benefit of hindsight, I realise I could have improved the on-site sketch itself, usually by simplifying it still further.

Brancaster Staithe, Norfolk is a good example of both, and the following demonstration shows how I used the sketch to produce a larger painting back in the studio.

Because I aim for a similar impressionistic feel in my studio work as I do when I paint outdoors, the demonstration uses the same simple four-stage line & wash technique I use for my on-site National Trust days, except that the larger 11x15in. (28x38cm) format allowed me to use a bigger brush (No. 12 Round) and a larger paintbox.

Step 1 - Planning

1. In my original sketch, I’d made the small boat on the right the centre of interest. The water in front helped lead the eye to it and I painted the boat red and white for further emphasis. Looking back at the sketch, I realised that the bigger boat on the left was unhelpfully leaning out of the composition, and that it would have made a simpler and better subject on its own.

2. I decided to keep the landscape format to give a feeling of wide open space, and to light the boat more strongly from the left so as to enhance the contrast between the lights and darks and make the boat really stand out. I considered relocating the water from the original sketch, but decided that the dominance of the boat in the revised composition made this unnecessary.

3. I kept the smaller boat on the left and the two posts on the bank as they helped balance the picture.

4. Finally, and importantly, I made a quick sketch (above) and used a few grey marker pens to check that I had a tonal pattern that would read properly.

Step 2 - Drawing

1. Using waterproof ink I lightly sketched the outline of the main boat about a third of the way in and a third of the way up: one of the classic positions for the centre of interest. Then I lightly sketched the outline of the grass bank to lead the eye towards the boat, positioned the smaller boat and hinted at the distant horizon about a third of the way down.

2. Happy that I had everything in the right place, I firmed up the lines of the main boat and added the rails, cabin openings, windows and mast, trying to maintain the same impressionistic style that I would have used on-site. Then I firmed up the smaller boat, the grass bank and the two posts.

3. I added vertical hatching to the shadow areas of the bank and boats, making sure I left the strongly lit areas untouched. Then I added horizontal hatching for the shadows cast by the bank and boats in a way that helped suggest undulations in the mud.

Step 3 - Initial washes

Keeping them as free as possible I applied the following washes in this order:
1. Sky wash was cobalt blue.
2. Distant marshes were raw sienna and raw umber. While still wet I dropped in a weak mix of Winsor blue (green shade) and raw sienna on the horizon; a few streaks of raw umber in the mid distance; and some warmer Indian red at the bottom to help the distant areas recede.
3. Mudflats I used wet-into-wet areas of cobalt blue to reflect the sky and weak Indian red for the mud. While still wet, I added weak French ultramarine in the shadow areas – and to give the sketch more variation.
4. Grass was a mix of Winsor blue and raw sienna –with some neat raw umber dropped into the wet wash for interest. I used raw umber for the posts.
5. Bank A mix of Indian red and raw umber.
6. Boats Weak cobalt blue for the small boat and even weaker for the light side of the main boat. Stronger cobalt blue for the cabin and stern. Raw umber for the mast and the rest of the stern.

Step 4 - Shadows and finishing touches

1. I applied a fairly strong transparent wash of French ultramarine and brown madder to the shadowed areas of the boats and the bank, to the cast shadows on the mudflats (trying to show the undulations), and on the grass to direct the shadows of the posts towards the main boat.
2. When the wash was dry, I applied a strong mix of French ultramarine and Indian red to strengthen the shadows at the bases and on the right-hand side of the boats, the cast shadow from the main boat, the left-hand cabin opening, and the area of bank immediately adjoining the main boat.
3. Using the same mix, I picked out a few darks on the top of the cabin, the underside of the rails and the shadow side of the mast.

Waiting For The Tide, Brancaster Staithe, pen and watercolour, 11x15in. (28x38cm)