Top 15 Tips for Painting a Portrait with Water Mixable Oils

In this article, I want to share some of my top portrait painting tips for water mixable oils with you. Water mixable oils have been my go-to painting medium for a long time. Over the last few years, I’ve gained a lot of experience using them and adapting traditional oil painting techniques to this wonderful medium. Water mixable oils offer a great alternative to traditional oils, eliminating the need for solvents and making the cleanup much easier.

Many of the techniques I’ll discuss here apply to both traditional and water mixable oils, but I’ll also cover a few medium-specific considerations to help you get the best results.

Here's my YouTube video that showcases all these tips on a portrait I recently completed:

1. Start with a Thumbnail Sketch

Before I even pick up my paints, I like to make a quick thumbnail sketch to work out the composition and value relationships. A thumbnail is a small, loose sketch where I focus on the big shapes rather than details.

I usually use a graphite pencil for this because it makes it easy to adjust things, but you could also use charcoal or even wet media. The point of this step is to break your composition down into big simple shapes and value zones, which will make your painting more cohesive. It can also help you figure out the best way to place the figure on the canvas and see the flow of the gesture better.

For this portrait, I broke my composition into three main value zones. Doing a thumbnail beforehand helped me decide where I wanted the most contrast and how I’d guide the viewer’s eye through the painting. Having a clear value plan before I start painting makes the process much easier down the line.

Thumbnails are great for simplifying your compositions and seeing the flow of the gesture better.

2. Know Your Tools

One thing I always recommend is getting to know your tools before you start painting. For example, if you're using water mixable oils, it's best to familiarise yourself with the properties of these paints and the mediums used with them before you jump into a big project.

Water mixable oils are real oil paints. The only difference separating them from traditional oils is that they contain an emulsifier, which allows them to be diluted with water. This emulsifier evaporates as the oils cure, so once they’re dry, they’re practically indistinguishable from traditional oils.

Here’s my hot take: I think that some of the issues that are attributed to water mixable oils are actually endemic to the Winsor&Newton Artisan line, which is effectively a student-grade line. I primarily use Cobra, Holbein, and Daniel Smith, which are professional-grade and have excellent pigmentation and consistency.

3. Focus on Proportions and General Outline First

One of the worst mistakes in portrait painting is messing up the proportions. If the structure is off, no amount of detail will fix it. That's why I always start by establishing the main proportions and general outline before doing anything else.

To make sure my proportions are correct, I use a method called comparative measurement, which means that I constantly check:

1. How different elements relate to each other in size;

2. At what angle the major lines in the figure are.

I use my brush as a measuring tool and compare distances and angles as I go. I also step back, squint, and check my work in a mirror to help spot proportional errors that I might not notice up close.

Remember that, while there’s nothing wrong with making mistakes, fixing them as early as possible will save you a lot of frustration later on. That’s why it’s best to establish the main proportions early—catching mistakes at this stage is much easier and saves you from having to fix them later when you’ve already invested time in details.

Establishing the main proportions early on will help you lay in a strong foundation for your painting.

4. Emphasise Big Shapes (Including Negative Spaces!)

Instead of getting caught up in the details too soon, try to focus on the overall silhouette and the large value zones that define the structure of your composition.

One thing I also pay attention to is negative spaces, i.e. the shapes between and around the subject. These gaps act as visual anchors and can help make the composition stronger. An example would be this triangle created by the bent arm of the figure, where the back of the chair peeks through.

Make use of the big shapes and negative spaces to make your composition stronger.

Giving negative spaces clear shapes can make the gesture of the figure more distinct and interesting. Squinting at your reference can help simplify complex forms into clear, bold shapes and keep the composition cohesive and unified, even when you start building up the detail later on.

5. Don’t Overuse Water

At no point in this portrait do I use water to thin my paints. While water mixable oils allow you to use water as a solvent, I avoid using it for anything other than cleaning my brushes. Adding too much water can break down the paint structure and make it look chalky and streaky when it dries. This is especially noticeable with skin tones—they tend to lose their richness and depth when the paint is too diluted, making the portrait look flat and lifeless.

For the underpainting, I don’t mix my paint with any additional mediums and apply it straight from the tube with a large hog’s hair brush to cover the entire canvas as quickly as possible and establish context early on. If you find that your paint has too much drag, I would recommend using a bit of specialised water mixable medium, such as Cobra’s 091 painting medium, which doesn’t alter the drying time while improving the flow of the paint.

Again, I find that many of the issues people attribute to water mixable oils— such as dull colours, patchy textures, or difficulties with blending—are often linked to overusing water during the painting process. Keeping water to a minimum not only preserves the paint’s vibrancy but also gives you better control over your brushwork, making the overall painting experience much smoother.

Try replacing water with specialised mediums to improve the painting experience and archival qualities of your work.

6. Work from General to Specific

I avoid working on details or highlights before I have a solid foundation. That’s because, when you paint a portrait, it’s easier to start with the big picture and gradually work your way to the details, which applies not just to water mixable oils but to any painting medium. This means focusing on the larger shapes, values, and structures before getting caught up in refining facial features and other small details. I begin by blocking in large areas of colour to establish the main forms and relationships, and this applies to the face as well.

The goal is to create a strong foundation where the proportions, value relationships, and composition are solid and work together in harmony. Once I’m happy with the overall structure, I start gradually refining the painting, carving out the smaller shapes, adjusting the edges, adding more precise colour transitions, and developing the facial features with more detail.

I avoid getting caught up in the details, such as facial features, until I have a solid foundation of colour and value zones.

7. Put Values First

Another tip for creating a strong foundation for your painting is to think about values as the backbone of your painting because they are what holds the entire structure together. No matter how accurate your colours are, if the values are off, the portrait will also be off.

Value refers to how light or dark something is. It is at the foundation of our visual perception, although we don’t always realise it. I like to establish context for my painting by covering the entire canvas as quickly as possible to make sure that no value exists out of context, because context is everything when it comes to values. You’ve probably already seen visual illusions where the same square of colour will look lighter in one environment and darker in another environment. That’s exactly what I mean when I talk about seeing values in context.

Here's an example of a visual illusion that demonstrates the importance of seeing values in context. Square 1 is the same value as Square 2. Image source: James Gurney's blog "Gurney Journey".

Strong value relationships and distinct value zones will carry your portrait, even if you use a compressed value range. Try squinting when you look at your painting or your reference to simplify what you see and make main value zones to stand out more clearly.

8. Reflect Skin Colour and Value Variations

When you are working on a portrait, it’s important to remember that the skin doesn't have a single uniform colour. Different parts of the skin have subtle shifts in hue and value, which are influenced by blood flow, bone structure, ambient lighting, and other factors.

For instance, the face can typically be divided into three colour zones:

• The forehead tends to be slightly cooler and lighter, often leaning toward yellower tones due to the thin skin over the skull.

• The mid-face (cheeks and nose) has the most warmth and redness due to increased blood circulation.

• The lower face (jaw and chin) is often greyer and darker than the rest of the face.

These natural variations help give the skin a lifelike quality. Even on other areas of the body, skin will vary in temperature— e.g. on the hands, fingertips tend to be redder, while knuckles and veins have cooler undertones. Recognising these subtle differences can make your portrait feel more vibrant and realistic, and pushing them can even make skin "vibrate".

Remember that skin has subtle shifts in colour and value. Using a single uniform colour for skin will make it look flat and unrealistic.

9. Don’t Overuse White

While white is often necessary for mixing lighter colours, overusing it can kill the warmth and vibrancy of your portrait. It’s tempting to reach for white to brighten skin tones or create highlights, but adding too much can make your colours look chalky and unnatural. White also tends to cool down colours, which can be useful in certain areas like highlights on the forehead, but if overused, it will drain the life out of your portrait.

The problem with titanium white is that it’s a very strong, opaque pigment, which tends to overpower any other pigment it's mixed with. That’s why I add my water-mixable version of the Velazquez medium (stand oil + fast-drying medium + chalk) to Titanium White to make it behave more like Lead White, which is a lot less opaque and chalky. Another thing you can do is mix in other lighter pigments for your highlights, such as yellow ochre or naples yellow, which will help you maintain the richness of colours while adjusting the value, so the portrait stays vibrant and dimensional.

10. Don’t Overuse Black

Another extreme to avoid is using too much pure black in your portraits. While it might seem like the easiest way to create deep shadows, Ivory Black can easily make them look flat, muddy, or too cool in temperature. I personally avoid using ivory black because it has a very cool undertone that can drain the warmth from a portrait. Overusing black can diminish the vibrancy of your colours, especially when mixed with reds or yellows, turning them muddy instead of creating natural-looking darks.

Instead, I prefer using a combination of Vandyke brown and Raw Umber to achieve rich, dark values without losing that natural warmth. This also adds depth to my paintings, without creating harsh contrasts.

I used pure Vandyke Brown for the dress, which made it warm but also translucent thanks to the transparent quality of that paint.

11. Use a Limited Palette

One of the most effective ways to create harmonious-looking portraits is to use a limited palette. My typical portrait palette consists of a cool and a warm red (Quinaquidone Rose and Terra Rosa), a couple of earthy yellows (Raw Sienna and Yellow Ochre), white (the water-mixable "Lead White" replacement I mentioned above), Raw Umber and Vandyke Brown for the darkest accents. I will also add more colours if the painting calls for it, but these are enough for most purposes. This earthy palette keeps everything grounded, and nothing will usually go outside the gamut created by these pigments.

A limited palette helps maintain colour harmony naturally because all the colours in the painting are connected through shared mixtures. It makes the colours feel unified without even trying. It also makes colour mixing more predictable, making it easier to control the values and temperature shifts without getting overwhelmed by too many options.

Limiting the number of colours you use in your portrait will naturally make it more harmonious.

12. Keep Shadows Thin and Translucent

Keeping your shadows thin and translucent will help create a sense of depth and luminosity in your portraits.Many artists also recommend avoiding to use white in the shadows, but keeping them thin and transparent is probably even more important. Thick, opaque shadows can make the painting look heavy and flat.

I try to establish my darkest values early on and then carefully build up lighter tones on top. This helps shadows feel like they’re part of the form and not just sitting on top of it.

13. Make the Eyes Darker Than You Think

One of the most important tips when it comes to painting the eyes is to make them darker then you think they should be. The eye is set deep within the eye socket, which is usually in shadow because of the way it recedes into the skull. The whites of the eyes called the sclera are especially misleading because our brain is tricking us to see them as white, but, in reality, the sclera is rarely pure white and is actually pretty close to the value of the skin. If you paint it too light, it can make the eyes look bulging and unnatural. I usually mix a greyed-down version of the surrounding skin tone to keep the eyes in harmony with the rest of the face. The irises also tend to be darker than you’d expect, especially around the edges and under the upper eyelid. Balancing the values in the eyes will help you avoid having them look crazy or unrealistic, and a few well-placed shadows and highlights can really make them pop.

If you paint the sclera (the white of the eye) too white, you risk ending up with bulging, unnatural looking eyes.

14. Create a Strong Focal Point

Speaking of making things pop, it’s important to think about where your focal point is and how you want to make your portrait interesting. As artists, we have the power to guide the viewer’s eye, and the focal point is where you want it to go first. Everything else in the painting should support that. In portraits, this is often the eyes, but it doesn’t have to be. In fact, I usually prefer to make the eyes stand out less in order to add to the mystery and atmosphere of the piece. However, I’m making this piece as a sample for my commissions page, so I want to make it more conventional looking than my original work.

Here are some tools you can use to make the focal point stand out:

• Value contrast: Strong light-dark contrast naturally draws the eye.

• Shape contrast: Unique shapes stand out against repetitive patterns.

• Hue contrast: The red notes on our portrait are made stronger by the green background.

• Saturation contrast: The most intense and pure colour will dominate the scene.

• Edge contrast: Sharp edges catch the eye, especially among softer edges .

• Texture contrast: A textured object will stand out on a smooth surface.

15. Don’t Be Afraid to Experiment!

Lastly, one of the most important tips is to experiment and embrace mistakes. It’s easy to get caught up in trying to make every brushstroke perfect, but the reality is that growth comes from pushing boundaries and trying new things. It's how you improve as a painter.

For instance, when I was in the final stages of creating this painting, I thought I’d add more visual interest to the dress by adding more texture to it. Later that day I went to a local museum and realised that keeping the dress flat would be better, so I came home, took my palette knife and scraped the thick paint off the dress.

Mistakes aren’t failures; they help us understand what works and what doesn’t as well as guiding us on the path to finding our own art style. If you’re too focused on avoiding mistakes, you’ll hold yourself back and miss opportunities to develop your style and push your painting to the next level. So don’t be afraid to mess up—it’s part of the process, and every painting, successful or not, will teach you something new.

And here's the final result!

Final Thoughts on Painting a Portrait with Water Mixable Oils

Water mixable oils offer the same depth, richness, and flexibility as traditional oils, with the added benefit of easier cleanup and solvent-free painting. If you account for their unique properties, take the time to understand your tools, and focus on strong composition, value control, and colour harmony, you can create stunning portraits with this versatile medium.

I hope these tips help you in your portrait painting journey! Feel free to check out my top 10 oil painting exercises for beginners, which go into more detail on how you can understand your tools better, learn to see values and larger shapes, practice colour mixing, etc.

By the way, if you’re interested in commissioning a custom portrait similar to the one above, check out my commissions page. Let me know if you have any questions, and feel free to share your own tips in the comments below.