How to Set Up a Plein Air Kit for Portfolio Work

Plein air painting — painting outdoors, in front of the subject — is one of the oldest ways to train the eye. It is also one of the best sources of observational work for an art school portfolio. Yet many students try it once, struggle, and give up. The reason is rarely talent. It is usually the kit: too heavy to carry, missing one essential item, unsafe to fly with, or impossible to get home without smearing the painting.

This guide is about the kit and the routine around it. It explains why painters went outdoors in the first place, how to choose one medium and build a kit around it, how to deal with sun, solvents and air travel, how to get wet work home, and how outdoor studies become portfolio pieces under the rules schools actually publish. Where we could not verify a claim from an official source, we say so.

The French term plein air means “open air”. Britannica defines plein-air painting as the practice of painting landscape pictures out of doors. The practice is older than Impressionism. From the 1820s, painters gathered at Barbizon, at the edge of the Forest of Fontainebleau, to sketch from nature. The Metropolitan Museum of Art notes that Corot always returned to the studio to work through what he had seen, while Daubigny pushed canvases to an unusual degree of completion outdoors, painting from a boat he had turned into a floating studio.

A small invention made outdoor painting practical. According to the Smithsonian’s Archives of American Art, the American painter John Goffe Rand invented a collapsible tin paint tube while living in London and received a US patent for it in 1841. Before that, painters stored mixed paint in animal bladders, which dried out. Winsor & Newton began selling paint in tubes soon after. Smithsonian Magazine quotes Renoir crediting tubed paint as the precondition for Impressionism itself.

That history carries a practical lesson. The Barbizon painters treated the outdoor study as raw material and finished in the studio; the Impressionists tried to finish on site. Both are legitimate. Before you pack, decide which you are doing today: gathering information for later, or completing a picture now. The answer changes the size of your support, the medium and how long you stay.

A frequent kit mistake is bringing everything. A kit that tries to support oil, watercolor and pastel at once is heavy, slow to set up and full of things you will not use. Choose one medium per outing and one target session length. Then build the kit backwards from those two decisions.

For most applicants starting out, a dry-media or watercolor kit is the right first step. It lets you go out often, which matters more than any single piece of equipment. Oil is rewarding but asks for more organisation, and it raises the safety and transport questions covered below.

Every kit shares a base layer: a bag you can carry comfortably for the distance you plan to walk, a drawing board or panel holder, clips, a pencil and eraser for the first lay-in, paper towels, a rubbish bag, water to drink, and a small notebook for notes on time, weather and light. Then add the medium-specific layer.

Watercolor and gouache

• A compact palette of pans or tube colours squeezed out at home and allowed to set
• Two or three brushes, including one large wash brush
• Water container with a lid, and a second for clean water if you can carry it
• Paper: a block glued on all sides resists buckling better than loose sheets. Arches lists its 300 gsm watercolor paper as 140 lb, a common working weight
• Gouache: a small spray bottle to keep paint workable in dry air

Oil

• A pochade box or a light easel with a palette surface
• A limited palette of tube colours
• Rigid panels rather than stretched canvas — they fit carriers and resist wind
• A sealed metal or glass container if you bring any solvent, and only a small amount (see the safety section)
• Plenty of paper towels, and a sealed bag for oily waste

Acrylic

• A sealable palette or a “wet” palette to slow drying
• Water for cleanup in a lidded container
• Panels or heavy paper
• A medium that extends working time, if you use one in the studio

Dry media

• A sketchbook with paper suited to your medium
• Two or three grades of pencil, or a pen and ink
• A viewfinder — a small rectangle cut in card — to frame the motif
• Fixative only if you will use it on site and not fly with it (aerosols, below)

How you stand or sit decides how long you can work. A sketchbook on the knee is enough for drawing. For painting, most people need either a tripod easel with a panel holder or a pochade box that sits on a tripod or on the lap. A light folding stool turns an hour into two. Test the whole setup in a park near home before you rely on it on a trip.

Sun on the painting surface is a frequent problem. Writing in Plein Air Magazine‘s OutdoorPainter, the artist Kathleen Hudson notes that with the panel in direct sunlight you may compensate and end up with a painting much darker and greyer than you intended; the watercolorist Robin Purcell advises keeping the sun off your paper. This is practitioners’ advice rather than a formal standard, but it is easy to apply: put the board in shade, turn your back so your body shades it, or use a small umbrella. Check your values again indoors before you call a piece finished.

A watercolor dries before you pack it. An oil painting may stay wet for days. Wet panel carriers exist for exactly this reason. RayMar, for example, describes a carrier that holds up to six panels, two back to back in each of three moulded slots, made of fluted plastic with a strap — and notes that it is designed for panels rather than stretched canvas. Whatever you use, the principle is the same: the wet surface must not touch anything.

Two habits help. First, work on a standard panel size so that your carrier always fits. Second, write the date, place and time on the back of each panel or sheet before you start. When you later build a portfolio or a series, that information is the record of your practice.

Read the label

In the United States, the Labeling of Hazardous Art Materials Act — enacted in 1988 and in force since 1990 — requires art materials sold to consumers to be evaluated by a toxicologist for chronic hazards, and the label must state that the product conforms to ASTM D-4236. The Art & Creative Materials Institute (ACMI) adds its own seals. The AP (Approved Product) seal means the product contains no materials in sufficient quantity to be toxic or injurious to humans, including children. The CL (Cautionary Labeling) seal means it is not hazardous when used as instructed, and that you must read the full label.

Pigments

Some pigments carry warnings. Golden Artist Colors explains that it places California Proposition 65 warnings on products containing compounds of cadmium, cobalt, lead, chromium or nickel, among others, and that cadmium colours should not be spray-applied. Gamblin states that cadmium and cobalt colours are safe when used as intended — the risk comes from breathing dust, for example when sanding. Outdoors, the practical rules are simple: do not eat while your hands are covered in paint, wipe and wash before you touch food, and never sand dry paint.

Solvents

Odourless mineral spirits are still solvents. Gamblin, which makes Gamsol, says that even with aromatic compounds refined out, studio air should be changed ten times an hour, that you should use only as much as you need, and that it should be stored in sealed glass or metal containers. Used solvent can be left to settle so the pigment sinks; the clear portion can then be poured off and reused. Oily rags should be hung to dry before disposal, and waste should be disposed of according to local rules.

Outdoors, the simplest approach is to avoid solvent altogether. Gamblin describes a solvent-free brush routine: wipe the brush, dip it in safflower oil, wipe again, and clean thoroughly at home. That removes the container, the smell and most of the risk from your field kit.

About half of our students attend secondary schools in the US and come home to Seoul in the holidays, so they fly with materials often. The rules are clearer than most people think.

Three practical conclusions. Do not fly with any solvent, including odourless spirits — we found no official approval for them, so buy a small amount at your destination or go solvent-free. Check Section 14 of a product’s Safety Data Sheet if you are unsure whether a paint is flammable, as the FAA advises. And leave aerosol fixative at home; buy it locally if you need it. Under the TSA liquids rule, tubes in your cabin bag count as liquids or gels, so either keep them to 100 ml each in your one quart-sized bag or put them in checked luggage. Rules can change; check FAA and TSA pages, and your airline, before each trip.

On site, resist the urge to start painting immediately. Walk around. Use a viewfinder to frame two or three possible compositions, and make small thumbnail drawings of each. Choose the one with the clearest structure of light and dark. Then make a value sketch before any colour goes down. Outdoors, the light will shift while you work; a value plan decided in the first minutes is what keeps the picture coherent as shadows move.

Block in large shapes first, then work toward detail. Stop while the light still resembles what you started with. Before you pack up, photograph the motif and the study side by side, and write two lines in your notebook: what worked, and what you would change. Those notes are as valuable as the painting. Over a season they show how your seeing has developed — and that development is what a portfolio should make visible.

No school asks specifically for plein air painting. Several, however, ask for or recommend work from direct observation, and all of them set rules about originality. Those rules decide how outdoor work belongs in a portfolio.

Plein air work is observational by definition, so it answers the requests above directly. Three suggestions make it stronger in a portfolio. First, show a series rather than a single study: the same place at different times of day, or one subject in three media, shows sustained looking. Second, show the bridge to studio work: a field study next to the larger painting you developed from it, in the Barbizon manner, shows how you think. Third, photograph the work well — evenly lit, square to the camera, colour checked against the original. A good study badly photographed reads as a weak study.

Outdoor practice also connects naturally with other traditions. Korean ink painting has its own history of painting real scenery; see our guide to ink wash techniques. For colour practice, our guide to dancheong as a design system shows how a disciplined palette can carry over into contemporary work.

A good kit disappears. When it works, you stop thinking about equipment and start thinking about light, structure and colour. Pack less, go out more often, keep notes, and let the studies accumulate into a record of how you see.

Royal Blue Art & Design, in Apgujeong, Seoul, is led by a director with 19 years of experience in US art school admissions. We help students build observational practice into portfolios that meet each school’s published requirements.

Sources: Britannica (plein-air painting) · The Metropolitan Museum of Art (The Barbizon School) · Smithsonian Archives of American Art (John Goffe Rand) · Smithsonian Magazine · FAA PackSafe (Paints and Solvents; aerosols) · TSA (What Can I Bring?; liquids rule) · ACMI (materials safety) · US CPSC (art materials, LHAMA) · Golden Artist Colors (health and safety labeling) · Gamblin (studio safety; guide for schools) · Arches (Aquarelle) · RayMar (wet painting carriers) · OutdoorPainter (Plein Air Magazine) · admissions pages of Pratt, RISD, SVA, SAIC and Parsons. Checked 2 October 2026.