Скачать или смотреть What are the 3 rules of oil painting, and how seriously should you take them? ✍️✨

Thanks to my brother for creating the music for this video!

You may have heard about the 3 rules. These are fat over lean, thick over thin, and slow drying over fast drying. A lot of artists find these rules confusing and either choose to ignore them or are put off using oil paints because theyre intimidated by them.
So I want to break them down to show how they are all to do with quite a simple concept, which is to increase the flexibility of your painting with each layer, and explain why this is important to prevent cracking in the future.

Imagine that you applied a thin, brittle cracker over a a soft, thick slice of bread - it’s more likely to crack if you press it gently than if they’re the other way around. And this is what the 3 rules are about.

So let’s define a layer: this is just when you apply wet paint over dry paint. This means that if you are painting wet on wet, using direct, impressionistic painting techniques, where the whole painting dries in one go, then you don’t need to apply the 3 rules.
These rules also don’t apply to acrylic painting because the chemistry and drying times are different.

But if you are using layers in oil painting, which we call indirect painting, then you always need to consider the 3 rules.

2 of the rules rules of oil painting, Thick over thin & slow drying over fast drying are pretty simple concepts and are both there to ensure that you don’t apply a fast drying paint layer over slow drying paint layer. A dry layer over a not yet-dry layer that is still in the process of curing will pull and twist the layer above, making it crack. This goes to lots of things in life, for example nail polish will crack if you add a top coat before the bottom layers are dry.

So to make sure you’re following these rules you want the layers to get thicker and more textured, not less with each layer as well as check the drying times of your oil mediums and paint colours to make sure the later layers won’t dry faster than the earlier ones.

One way to do this is to use underpainting white, earth colours, or other fast drying colours in your lower layers. And save your textured, impasto brushstrokes to the end so they have plenty of time to cure and plasticize fully.

The oil painting rule Fat over lean is perhaps a little more confusing. It helps to know that when we say fat or lean in oil painting it means the paint contains more or less oil. Simply put oil painting is just a combination of pigment and binder which is typically linseed or another oil medium, fat paint has more oil in and lean paint has less. So you can use the amount of oil medium you add to the paint to determine how fat it is.

To follow fat over lean you can use your solvent and oil medium to either premix jars with increasing amounts of oil, adding solvent if you want to thin the paint. Or you can do what I do and mix increasing amounts of oil medium with each layer on the palette.

But there is misinformation about fat over lean. I’ve seen videos where artists refer to the texture of an oil medium as being more or less fat or compare the fattyness of oil mediums. But all types of oil medium, no matter thick or thin in texture are equally fat. Another way to understand fat or lean is to think of it as the ratio of pigment to any other ingredients that stay in the paint after it dries, usually oil but also resins.

So Fat is the binder in paint - anything that isn’t pigment that won’t evaporate. And all oil mediums - though they have differing levels of solvents - are designed to stay in the paint once it dries.

It’s important to remember solvent also thins the paint, making it fast drying and therefore brittle.
meaning to break it down you should use less solvent with each layer of the painting and more oil medium. Even though you may also add Solvent to your paint to make it more fluid, solvents are not fat cuz they evaporate out and don’t remain in the paint once it’s dry. So although Adding solvent to the paint doesn’t make it any leaner, because it evaporates out of the paint as it dries, it also won’t make the paint any fatter.

When people describe the science of oil paint and comparing drying times and mediums it all can sound pretty overwhelming. But all it takes to prevent cracking in the future is to bear in mind the three rules of oil painting fat over lean, thick over thin, and slow drying over fast drying, & simply ask yourself if each layer you add will dry slower and contain a little more oil than the last. The science is complex but the action is simple and that’s why the three rules are so useful to every oil painter.