The 3 Golden Rules of Oil Painting

If you want to know how to start oil painting, you’ll have to start drawing the objects surrounding you in everyday life. Drawing teaches you essential techniques that help you bring life to your art and learn how to paint effectively, especially when working with a medium as finicky as oil paint.

However, what will also help you paint is to learn oil painting basics, such as the three golden rules to follow. Although many ‘rules’ of art are more of suggestions than directives you’re obliged to comply with, oil painting has three rules that you must understand to add longevity to your paintings. Otherwise, they’ll undoubtedly crack and age poorly, which means your artwork won’t survive the test of time.

Here are the three golden rules of oil painting:

Fat Over Lean

Fat over lean applies to the additives you’ll be putting into your oil paint. Additives often fall under two categories: oils and solvents. Odorless mineral spirits and turpentine are solvents that will thin your paint, whereas linseed oil, Liquin, and safflower oil are oils that make your paint smoother and easier to paint with. Adding oil painting medium to paint results in a ‘fat’ mixture, and adding solvent leads to a ‘lean’ mixture. For this reason, ‘fat over lean’ just means that you must start your painting by adding layers of lean paint, or paint with solvent, then top it off with layers of fat paint or paint with mediums.

Why is this important? Lean paint dries faster than fat paint since the solvents evaporate quickly, accelerating the painting’s overall drying time. If you start with an oil-laden layer and overlay it with lean paint, the layer underneath will still be drying, curing, and changing dimensions, leading the top layer to crack. The top layer may even fall off altogether, so you must always start with a thin layer before working with fat paint.

Thick Over Thin

The wonderful thing about paint is that you can apply it in many different layers to achieve a specific effect. You can start with glazes, or very thin layers, leading up to impasto or thick layers. However, if you intend to paint in different thicknesses, it’s essential to start with thin layers and finish your painting with thick layers. That’s because oil paint doesn’t try as water-based paints do by evaporation, but by ‘curing,’ solidifying through oxidation. The thicker the layer is, the longer it takes to dry. Even when it feels dry on top, it usually isn’t completely solid yet!

For this reason, it’s best not to paint over it until it’s well and adequately cured, even if you want to add a thin layer on top. As mentioned in the previous rule, the thin layer will dry quickly and crack as the layer underneath slowly dries and changes shape. To avoid this, start with thin layers and gradually work your way to thicker layers. You can also paint with thin layers and add thick layer accents once the painting is finished.

Slow Drying Over Fast Drying

Not all colors are created the same. Some colors take longer to dry than others, even when you’re painting with one brand of oil paint. To avoid clashing dry times, start a painting with colors that dry faster and finish it with colors that take their time to dry. You can also mix in medium to your last layers so they take longer to dry, keeping the first rule in mind.

You may be wondering which colors dry fast and which ones dry slowly. Earth tones typically dry overnight, while jewel tones take much longer. Reds, blues, and yellows can take days or even weeks to dry completely. Blacks and whites can also take a while to dry. It’s best to go to your oil paint brand’s website for more information about the paint’s drying time or adjust it using thin or thick layers. 


Oil painting can be tricky to master. However, learning these three rules and applying them each time you paint will make you progress faster, encouraging you to explore new techniques and come up with gorgeous, long-lasting paintings you’ve always dreamt of creating. 

For more oil painting tips, be sure to check our guides! We have multiple teaching courses that cover oil painting for beginners, watercolor lessons, and more. View all lessons today to get started on your dream of painting beautiful landscapes!

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