Getting Started with Oils

Learn with an exhibiting artist Martin Kinnear RCA

A Painter’s Guide to Length, Grounds & Mediums

If you're feeling unsure about how oil paint should behave — maybe it’s drying too fast, refusing to blend, or just not giving you the finish you hoped for — you're not alone. These are some of the most common frustrations we hear from new and developing artists.

At the Martin Kinnear Studio, we believe that the key to unlocking your painting potential isn’t found in shortcuts or tricks — it's in understanding how your materials work. That’s why we’ve created this guide, based on Martin Kinnear’s Royal College of Art-accredited research, to help you take control of your oils from the very beginning.

Whether you’re just starting out, or retraining to build a more confident studio practice, this is where it begins.

Let’s Talk About Length — What It Is and Why It Matters

In oil painting, length is one of those deceptively simple concepts that affects just about everything — how your paint spreads, how it blends, how long it stays wet, and even how your colours appear once dry.

Length applies to three key elements: your paint, your surface (called the ground), and the mediums you mix in. If they’re working together, painting becomes intuitive. If they’re fighting each other, you’ll feel it immediately — in streaky blends, sticky textures, slow drying, or dull colour.

Most tube oils come in a soft, buttery consistency. That’s your baseline — but it’s up to you to adjust it based on what you want the paint to do. If it feels stiff and reluctant to move, it’s short. If it flows smoothly and blends easily, it’s long.

Here’s where things get interesting: you can make your paint longer by adding more oil, or shorter by thickening it with chalk or cutting it with solvent. Some pigments come naturally short (especially earth tones), while others are naturally greasy and flowy. Even the age of your paint can affect its length.

This is something Martin Kinnear teaches directly in his studio programs — learning to recognise and control the length of your paint is a cornerstone of studio literacy. It’s not just technique — it’s material intelligence.

The Ground Beneath Your Paint — and Why It Changes Everything

If you’ve never considered how your surface affects your paint, you’re not alone — but you’re also missing a powerful tool. What you paint on directly affects how your paint behaves.

A long ground is less absorbent — think smooth, sealed surfaces like aluminium panels or oil-primed boards. Paint sits on it, giving you more time to blend and a richer finish. But it also means slower drying and more patience required.

A short ground, by contrast, is absorbent. Unprimed canvas, MDF, or chalky gesso pulls the paint in, speeding up drying and locking in the first layer. It’s often easier for beginners to control — less waiting, more progress.

You can manipulate the absorbency of your ground, too. Want a longer surface? Add more binder to your acrylic gesso or oil it out before painting. Want it shorter? Mix chalk or marble dust into your primer. It’s all about knowing what result you’re aiming for and setting up your materials to support it.

In Martin's newly launched PRIMER program, this kind of material thinking is front and centre. It’s designed specifically for undergraduates, postgraduates and emerging artists looking to build a meaningful, self-directed practice — the kind of foundation every serious painter needs.

Mediums — Your Personal Paint Toolkit

Mediums are what you add to your oil paint to fine-tune how it works. They control drying time, texture, flow, and finish. The way you mix a medium can make your paint feel luxurious and slow, or punchy and dry.

A standard starting point is a 50/50 mix of drying oil and solvent. Want it to flow more and dry slower? Add more oil. Want it to dry quicker or feel tackier? Add solvent or chalk.

There’s also a wonderful world of short mediums — putty-like mixtures of oil and chalk — which are great for speeding drying and giving you crisp, textured handling. Cold wax and bodied oils offer even more control, though they take a bit more know-how to use effectively. (We’re always happy to help — just ask.)

At the studio, this is where a lot of painters have their “lightbulb moment.” The power to change how your materials behave — not by switching brands, but by understanding them — is transformational.

A Note on Fat Over Lean

If you’ve heard the phrase “fat over lean” but weren’t quite sure what it meant, here’s the short version: fat means oily, lean means less oily. Start with lean, finish with fat. It helps layers dry in the right order and prevents cracking.

Lean paint dries faster and tends to be shorter in feel. Fat paint dries slower, tends to be longer, and gives that beautiful rich sheen. It’s one of those classic rules that, once you understand the reasoning behind it, makes total sense — and makes your paintings more sound.

Take the Next Step with Martin Kinnear Studio

This useful guide is just the beginning. At the Martin Kinnear Studio, we offer more than tuition — we offer a complete pathway into contemporary oil painting, grounded in time-honoured methods and informed by leading-edge academic research.

Whether you’re a complete beginner or a returning artist looking to rebuild your practice, our structured programs are designed to support every stage of your journey. The Oils Program offers deep technical insight and hands-on training in oil materials and methods, while PRIMER supports artists seeking to build a sustainable, self-aware studio practice grounded in critical thinking and material fluency.

Both are shaped by Martin Kinnear’s study at the Royal College of Art and reflect the rigorous standards and exploratory thinking at the heart of his teaching.

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