There is more than one way to paint with oils. In this lesson, I’ll go over some common methods and techniques for you to get familiar with your choices. This lesson is not meant to overwhelm you—don’t think that you need to know all of these techniques straight away. It’s just to get you used to some terms you may come across in your reading.
Here are the topics we’ll be discussing:
Rule #1: Fat Over Lean
When oil painting in layers, each successive layer must be more flexible than the one underneath. This rule is maintained by adding more medium to each successive layer.
Explanation: Fat is the amount of oil you add to your paint and lean is the amount of thinner, solvent, or turpentine you add. The more oil in the medium, the fatter it is. Think about eating dinner—salad first, then the good (i.e. fatty) dessert at the end. The salad—the starter—is lean, meaning your paint will first have more thinner or solvent in it. The fat, which we use in the upper layers, has more oil. By the way, you won’t just use these mediums straight out of the container—you’ll mix them to come up with your own combination that works for you. We discuss this below. For more about painting in layers, see our Glazing in Oils lesson too.
Rule #2: Thick Over Thin
Explanation: Thick layers of oil color are best applied over thin under layers. Thin layers on impasto paintings are likely to crack.
Solvents are used to thin your paint and clean your brushes.
Mix a little of your turpentine or Gamsol into your paint to thin it out for the first layer–this is your “lean” layer of paint. This will help it dry quickly so you can start painting straight away, instead of waiting for it to dry before you move on.
Turpentine used to be used because it was the only option, but in the 20th century, odorless mineral spirits (OMS) were invented, providing a safer alternative to traditional turpentine. Gamblin makes a product called Gamsol which is one of the best OMS on the market. It’s made with the knowledge that it will come in contact with your body, so most of the bad stuff has been removed. It doesn’t smell and it has a high enough flash point that it can be shipped via airplane as a non-hazardous material. It’s better for you in the long run. It’s more expensive than, say, paint thinner from the hardware store, but your health and safety is worth it. Trust me.
Pro Tip: If you try to pour Gamsol into your solvent container the way that seems most logical (with the spout side down) it will spill everywhere. Pour it like this:
…and it won’t spill.
Mediums can be used for a wide variety of purposes, and one of the main reasons to use it is to give your paint a little bit of gloss. Mediums also help your paint flow better and can be essential in blending and adding depth.
Mediums are the fatty additives you add to your paint. There are thousands of different kinds you could use, but we suggest just using a simple alkyd medium. Gamblin makes Neo Megilp and Galkyd, and Winsor & Newton makes Liquin—all are very easy to use and there’s no need to worry about cracking.
Traditional mediums are sometimes made from toxic materials—they can crack, turn dark or yellow with age, and on top of all that, you have to remember precisely how much solvent or oil was in the last layer you painted so that you don’t add a lean layer on top of a fat layer. It’s a lot to think about, which is why we are streamlining the process and only using one alkyd medium.
For more in-depth information on mediums, see the appendices to this lesson in the Student Resource Center. Appendix A talks about solvents, Appendix B has info on oils, alkyds, and other additives, and Appendix C goes over some varnishes. If you’re interested in mediums beyond what I discuss there, then do your own research. Honestly, I think it’s part of the fun. The more you learn, the more options you have. It’s like Degas said, “Painting is easy when you don’t know how, but very difficult when you do.”
Oil Painting Techniques
Not only do mediums improve the flow of paints, they can help you achieve the look you want for your painting. Here are a few common techniques:
Alla Prima: Italian, “at once,” refers to a method of direct painting on a white canvas in which the artist finishes the painting in a single session. Also known as direct painting or wet-into-wet. Frans Hals used to paint portraits alla prima and later would go back and glaze into the clothing. (Note: you can employ more than one method of painting in a single painting—parts can be alla prima while other portions are glazed, just like Hals.)
This painting of Hals’ is entirely alla prima:
For more information on alla prima painting, see our lesson on it in the SRC here.
Plein Air: This is a direct painting technique that occurs outdoors. Think Monet. We go more in depth about this in our lesson Painting En Plein Air With Oils.
Underpainting: Also called “dead coloring.” An old master practice, artists will paint their entire painting first monochromatically (tonal only, i.e. black and white) to establish tonal range (lights and darks) and give volume to the forms. Later on, transparent colors will be added to give color to the whole painting. The colors used in underpaintings vary greatly between artists and schools. Old Master Italian painters preferred verdaccio (ver-DATCH-ee-oh), or green underpainting.
The green can be made by mixing Yellow Ochre with Mars Black or by using straight Terre Verte or Chromium Oxide Green plus Mars Black. Since green is the complementary color to red (and consequently, pink), it balances out the pinkness of flesh tones so they aren’t too overpowering. Terre Verte is a transparent color, so it’s a little tricky to use, especially if you’ve already laid down colored grounds on your canvas.
The French liked to use the grisaille (griz-EYE) method, which uses a neutral grey (usually Raw Umber and Black mixed).
After the underpainting is completely dry, color is glazed on top.
Just about any color can be used for an underpainting. If you continue through to our video tutorial lessons, you’ll see how Beginner’s School instructor Cynda Valle approaches underpainting and glazing in her work.
Glazing: This is the most traditional method of oil painting. The paint is built up over many, many layers using different glazing mediums. Watch this video from our instructor Cynda Valle to see how she goes about glazing: Glazing in Oil Paints).
Glazing is the build up of layers of transparent or semi-transparent color over dry underlayers. It is a lengthy technique where the effects in oil are unmatched when compared to other media. There are a lot of different mediums you can use in glazing.
The truth is, you could spend your entire life just researching and testing different glaze recipes. The possibilities are endless. Personally, as much as I like the old masters and want to be as close to them as possible, my health and my family’s health is more important to me, so I try to stay away from toxic painting supplies. I want to be able to keep learning about paint until I’m old and honestly, I want that for you too. We recommend Neo Megilp, Liquin, or Galkyd for glazing.
S’graffito: “S’graffito,” the technique of scratching into a wet oil film, can be done with the pointed end of a brush, painting knife or any scraping device. It is effective in defining outlines or details for expressive effects.
Sfumato (sfoo-MAH-toh): Italian for “softened,” or as I’ve heard too, “softened like smoke,” this term refers to making very soft, gradual transitions from light to dark. Leonardo da Vinci is responsible for this one and, of course, it shows up in a lot of his paintings. Although it’s seen in the Mona Lisa, my first art history professor explained sfumato with da Vinci’s Virgin of the Rocks:
Notice how all the darks are softened, almost smoke-like in their appearance? That’s sfumato. Here’s a close-up:
Soft. That’s the key to sfumato. Darks are faded out gradually with a very soft brush. Artists working with sfumato generally use earth tones (mainly umbers) and paint in many layers to keep things very soft. It can’t be done in one layer. There’s also no absolute rule I can give you for sfumato (e.g. “with Raw Umber, use a number 4 fan and sweep with an upwards motion”). I’m telling you about it because 1) it’s super important in art history (and I love that stuff), 2) you’ve probably either heard about it or will hear about it, and 3) if nothing else, it makes for good conversation at a cocktail party.
Let’s look at the multi-layered, soft, glazed effect of sfumato next to something like impasto, which (can) but usually doesn’t have as many layers as a glazed painting:
Can you see how the Da Vinci portrait painted with sfumato has much softer shadows? Let’s look really closely:
Big difference, huh? They both look about the same from far away, but close up, you start seeing the differences, and they’re huge. Bellows is painting very thickly, with a lot of paint, wet-into-wet. Da Vinci is rumored to have painted as many as 40 layers into Mona Lisa’s face. And both are amazing. What it comes down to is what you are personally drawn to and enjoy doing as an artist. The biggest difference between glazing and alla prima methods is visible brushstrokes—glazing effectively gets rid of all brushstrokes while the motion of the brush is very important to alla prima and direct painting methods.
It’s so hard to tell just on the computer screen, but trust me, this painting is thick. When I studied in Paris, the Centre Pompidou had an exhibition of Freud’s work and I went as many times as I could afford. It seems like he just piles blobs of paint on top of blobs of paint and it ends up looking like this. He’s one of my personal heroes and his paintings are fantastic in person—if you ever have the chance to see his work, by all means go.
Scumbling: This is when you use a dry brush to apply paint in a “scrubbing” manner over the top of another paint. Loosely brush a thin film of opaque or semi-opaque color over your underpainting. This may actually show through in places and can retain an important influence on the surface appearance of the painting. Here’s an example from Learn2Paint.info:
Can you see how the top parts of the waves look like they’ve been scrubbed in? If there was a lot of medium added to that, it would appear more fluid, but scumbling gives a sort of dry, transparent effect.
How Do I Start?
Begin with your underpainting. Underpainting can be done in monochrome using any just about color, or it can be done in full color if using fast drying colors. Because it is the first layer, it should be your thinnest layer of paint. Mix your paint down with solvent until it is very runny and resembles watercolor. After your underpainting is completed, you can begin adding alkyd medium to your paint.
Remember, you only need a small amount of medium. You want your paint to glide smoothly on the canvas. If it is too thick and difficult to move, add a little medium. If it’s too runny or clear (not enough pigment), you’re using too much medium—add more paint.
They attach to your palette with a little built-on clip. Both have lids so I can save my medium until my next painting session.
You’ll put your alkyd medium in one palette cup and clip the cups onto the side of your palette. When you start painting, pick up a little medium on your brush and add it to the paint or paint mixture you’re going to use. A good rule of thumb is to use less than 25% of medium to the amount of paint. You need very little medium.
Exercise: Experiment With Different Techniques
Get a blank canvas or piece of board at least 6” x 6” and start playing with your solvent and medium. Try some of the techniques listed above—which combination works best when you try to scumble your paint? Or scratch some s’graffito into it?
Next lesson: Basic Color Theory