Essential brushes for plein air painting trips

Why a small brush roll beats a big studio set

Packing for a plein air trip is an exercise in ruthless editing. You have a rucksack, a pochade box or a lightweight easel, a palette, a canvas or a watercolour block, and a finite amount of room left over for brushes. The temptation is to take everything, just in case. In practice, the painters who come back with good work are usually the ones who took four or five brushes they know intimately rather than fifteen they barely understand.

The good news is that landscape painting, for all its variety, asks the same handful of questions over and over. Can you lay a broad, even wash for sky? Can you taper a mark so it reads as a branch or a reed? Can you scrub texture into a hedge or a shingle beach? Answer those three and you can paint almost anything the British weather throws at you, from a grey Norfolk estuary to a sunlit Cornish headland.

Start with three shapes: filbert, round and flat

Almost every plein air kit can be built from these three head shapes, each in a couple of sizes. Understanding what each does best will stop you buying more than you need.

• Filbert — an oval head with a rounded tip. The workhorse of landscape painting, because it makes both a broad blocky stroke and a soft, tapered one depending on how you roll it. Ideal for foliage masses, cloud edges and hedgerows.
• Round — a pointed head with a full belly. Holds plenty of paint and comes to a fine tip, so it draws as well as it fills. Perfect for branches, fence posts, reeds, distant tree lines and fine detail.
• Flat — a square-ended head. Lays flat, crisp planes and sharp edges: roof lines, field boundaries, water reflections, and the dry-brush scumble that gives foreground texture.

If you paint in oils or acrylics, a small bright (a short flat) is worth adding for stiffer, more controlled marks. Watercolourists might swap one flat for a large mop or wash brush, since watercolour skies live or die on speed.

A practical four-brush kit for oils and acrylics

For a day out with a medium-sized board, this selection covers skies, trees and foreground without a single wasted brush.

• One large filbert, roughly 16–20mm wide, ideally in a stiff synthetic or hog bristle. This is your sky brush. It holds enough paint to cover a third of a 30 x 40cm panel before you reload.
• One medium filbert, around 8–10mm, for mid-ground trees, hedges and cloud shadows.
• One medium round, size 6–8, for trunks, branches, posts and any drawing you need to do on top of wet paint.
• One small flat or bright, around 5–6mm, for crisp accents, highlights and scratched-in texture.

Add a fifth only if your subject demands it: a rigger or liner for bare winter branches, or a small round for a signature and a few bright specks of light. Longer handles are generally better outdoors — they let you stand back at arm's length, which is exactly where landscape work wants you.

Watercolour and gouache: fewer brushes, more water

Water-based painters travelling light can manage with three brushes, provided they are generous.

• A large squirrel or synthetic squirrel mop for skies, washes and wetting paper. Squirrel holds water beautifully but points poorly; that is fine, because you will not be drawing with it.
• A medium round, size 10–12, in a springy synthetic. This is your all-rounder: shapes a hill, draws a gate, lifts a highlight.
• A small round or rigger, size 2–4, for fine lines, rigging on boats, dry grass stems and calligraphic marks.

Gouache painters should lean towards synthetic rounds and flats with a bit more snap, since the paint is opaque and rewards firmer, more deliberate strokes.

Fieldcraft: keeping brushes alive outdoors

A brush that has been jammed tip-down in a bag is useless by lunchtime. A few small habits make a real difference.

• Carry them in a roll or a tin, tips protected and slightly separated, rather than loose in a jar where they knock against each other.
• Never stand a brush bristle-down in water or solvent, even for ten minutes. The tips curl and the ferrule loosens.
• Wipe, don't scrub, on a rag before rinsing. Less solvent, cleaner colour, longer brush life.
• Take two rags — one for wiping, one dry for dry-brush effects and for cleaning your hands before you touch your sandwich.
• Reshape the tip with your fingers after rinsing and let brushes dry flat or head-up, never head-down.

In cold weather, natural bristle stiffens noticeably. A synthetic blend copes better with a British February, and it will survive being left in a cold car boot far more gracefully.

Spend your money where it shows

You do not need an expensive set. You need one or two good brushes and the discipline to leave the rest at home. Put your budget into the two you will use most: the large filbert or mop that paints your sky, and the medium round that does your drawing. Buy the best you can afford in those sizes, keep them clean, and replace them when the tip goes soft rather than hoarding a drawer of tired spares.

A short, familiar kit also changes how you paint. When there is only one brush in your hand and no decision to make, you stop shopping for tools and start looking at the landscape — at the way light sits on a wet field, at the weight of a cloud, at the particular green of a hawthorn hedge in May. That is where the paintings come from.