Watercolor mediums are essential tools that give artists the flexibility to push beyond the limits of traditional watercolor painting.
Whether you’re trying to extend drying time, create textured effects, or enhance the natural pigment transparency of your paints, these additives make it possible to customize the behavior of water-based pigments on watercolor paper.
In this article, we’ll explore the different types of watercolor mediums available, including granulation medium, gum arabic, and ox gall, and how they affect the paint flow and color mixing in your artwork.
By the end, you’ll have a clearer understanding of how these tools can elevate your technique, offering more control over everything from wet-on-wet techniques to glazing and layering.
You’ll learn practical tips for incorporating these mediums into your creative process while avoiding common pitfalls like overuse and unintended side effects on your final piece.
Gum Arabic: The Traditional Binder
Gum arabic is a foundational component of watercolor paints. It’s been used for centuries as the primary binder, responsible for holding water-based pigments together and allowing for smooth application on watercolor paper.
This natural resin, harvested from acacia trees, dissolves in water, making it the ideal medium for creating transparent layers and facilitating paint dilution.
Without gum arabic, watercolor mediums wouldn’t behave the way they do. It controls the paint flow, ensuring that pigments remain suspended in water and don’t simply run off the paper.
This binder also plays a significant role in the drying time manipulation—it slows the drying process just enough to allow for delicate wet-on-wet techniques or smooth washes without harsh edges.
One of the advantages of gum arabic is its effect on pigment transparency. By diluting the paint, you can achieve light, delicate layers that allow for easy glazing and color mixing. This is critical for maintaining the subtle, fluid transitions that watercolorists rely on.
Gum arabic also adds a slight gloss to the dried paint, which enhances the final appearance without overpowering the natural lightfast pigments.
However, this can be a downside for those who prefer a matte finish, as the gloss can occasionally be more noticeable than desired.
When mixed in higher concentrations, gum arabic can thicken the paint, which helps with controlled bleeding and dry brush techniques, offering more texture and control over the pigment suspension.
This makes it a versatile component in achieving a range of effects, from soft, flowing washes to sharp, detailed strokes.
A potential pitfall of using gum arabic, though, is that too much can cause the paint texture to become overly stiff, leading to a less natural flow of the paint layers.
Also, it’s worth noting that it can attract dust and dirt, as it remains slightly tacky after drying in humid environments.
This means artwork may need extra care, especially if it’s going to be displayed for long periods without protective varnish.
Finally, gum arabic’s solubility in water means that even after drying, watercolor paintings remain vulnerable to water exposure, so be mindful when handling or framing your work.
Ox Gall: Enhancing Flow and Wetting Properties

Ox gall is a liquid additive commonly used in watercolor painting to enhance the flow and wetting properties of the paint.
It’s derived from the bile of cows and has a significant impact on how pigments behave on watercolor paper.
By reducing the surface tension of the water, ox gall allows for smoother, more even paint flow, especially when working with wet-on-wet techniques or attempting to cover large areas with a wash.
When added to watercolor mediums, ox gall increases the ability of the paint to spread across the surface without pooling or streaking.
This can be particularly useful when you’re trying to create smooth washes or when layering transparent colors in glazing techniques.
It helps the paint adhere better to the paper and improves the pigment’s dispersion across the surface.
Ox gall also plays a role in color mixing. It allows pigments to mix more naturally on the page without creating harsh boundaries between colors.
This makes it easier to achieve subtle transitions and blending. For artists who rely on creating detailed gradients or soft layering of color, ox gall is an indispensable tool.
However, there are a few potential downsides. Overuse of ox gall can lead to overly diluted washes, where the pigment loses its strength and vibrancy.
Additionally, because it changes the surface tension, it can sometimes cause unintended spreading, making it harder to control where the paint goes, especially in detailed work.
The most significant pitfall is the unpredictability it introduces. Some papers react differently to ox gall, especially hot-pressed paper.
You might end up with edges that blur or areas where the paint lifts more easily than expected.
Texture and Thickening Mediums
Texture mediums are designed to add body and dimension to watercolor paints, giving them a physical texture that stands out on the watercolor paper.
These mediums can be mixed directly with the paint to create raised areas, which give more depth to the painting and allow for a range of texture manipulation techniques.
This can be particularly effective for abstract works or when creating detailed textures, such as rough landscapes or gritty surfaces.
One of the most commonly used options is granulation medium, which causes pigments to clump together, giving the final layer a mottled or speckled appearance.
It works best with granulating pigments, allowing the artist to highlight specific details within the paint layers.
If you’re looking to add controlled bleeding or variations in color texture, granulation medium can bring an unpredictable yet unique effect.
For artists who prefer more control over the paint’s thickness, a thickening medium is used.
It helps maintain the paint texture when working with heavier brushstrokes or when creating specific, bold marks that need to retain their shape on the page.
By adjusting the consistency, it’s possible to achieve effects that would normally require another medium like acrylic.
Another additive to consider is texture paste, which provides even more body. When applied, it dries to a hard surface that can be painted over, allowing for greater control of watercolor flow over textured areas.
You can blend watercolor pigments directly into the paste or apply the paint afterward, depending on how much texture you want to achieve.
But here’s the thing: while these mediums offer a ton of creative options, they come with their own challenges.
Overuse of texture or thickening mediums can easily overwhelm the subtle nature of transparent watercolor.
Too much medium can shift the painting towards the look of acrylic ink or even oil paints, removing that classic, fluid watercolor feel.
Then there’s the drying time issue. Thickened watercolor tends to dry much slower, which can cause issues with layering and glazing techniques.
This can be a huge obstacle if you need to work quickly or build multiple layers of color. It can also lead to unwanted cracking or peeling if not applied carefully.
Lifting Preparation Mediums

Lifting preparation mediums are designed to make it easier to remove or lift watercolor paint from the surface after it has dried.
This is especially useful when you need to lighten areas, fix mistakes, or create highlights in a painting without damaging the watercolor paper.
When applied before painting, this medium prevents pigments from staining the paper too deeply, giving you more control over staining colors.
The process is straightforward. You apply the medium to the area where you might need to lift paint later.
Once it’s dry, it forms a protective barrier between the paint and the paper. This allows for pigment lifting without disturbing the paper fibers, making it ideal for achieving subtle effects or making corrections.
Lifting mediums can also be helpful when working with transparent watercolor.
If you’ve applied too much pigment and lost some of the transparency you were aiming for, this medium allows you to carefully remove layers of paint while preserving the texture and luminosity of the remaining watercolor layers.
However, there are limitations. Over-reliance on lifting mediums can lead to overworked surfaces, especially if the paint has been heavily applied.
Cold-pressed paper holds up well under multiple lifts, but hot-pressed paper can show signs of wear if too much lifting is done, making it less suitable for intricate correction work.
The risk with lifting mediums is that they may leave a residue if not applied evenly, which can interfere with subsequent color mixing or layering techniques.
This can lead to areas where the paint behaves unpredictably, either spreading unevenly or refusing to adhere as well as you’d expect.
Iridescent and Experimental Mediums
Iridescent mediums add a metallic or pearlescent effect to watercolor paints, giving the artwork an extra dimension when light hits it.
When mixed with the paint, they create a shimmering quality that catches attention, especially in areas of high contrast.
They’re perfect for highlights or for adding texture to specific elements, like reflective surfaces, water, or even abstract details where a metallic sheen enhances the composition.
These mediums can be mixed directly with the paint or applied separately over a dry layer.
The key is to balance the shimmer with the transparency of the watercolor layers.
Too much iridescent medium, and you lose the transparent watercolor quality, making it feel more like acrylic ink than a fluid, traditional watercolor.
Experimental mediums push boundaries beyond the typical. Think texture pastes infused with mica, or granular additives that give unusual effects when dried.
These aren’t your everyday watercolor mediums; they’re designed for those moments when you want to break away from convention.
When used sparingly, they can elevate certain areas of your piece, adding depth or texture where needed.
But here’s the catch: they’re unpredictable. Some of these mediums can dry in unexpected ways, sometimes warping the watercolor paper or changing the paint texture in ways you didn’t anticipate.
Over-reliance on these experimental elements can risk making the artwork feel overworked or gimmicky, losing the essence of watercolor’s natural fluidity.
Blending Mediums for Slowing Drying Time

Blending mediums are specifically formulated to extend the drying time of watercolor paints, allowing for more control when working with delicate transitions or large areas.
They slow down how quickly the water evaporates, giving you more time to manipulate the watercolor washes and achieve smoother color mixing.
This can be particularly helpful in wet-on-wet techniques, where the longer the paint remains wet, the more seamlessly you can blend transparent watercolor layers.
By using a blending medium, you avoid the harsh edges that can appear when the paint dries too quickly. It’s like adding a buffer that holds the water longer, keeping the pigment suspension active.
This becomes critical when working with detailed layering techniques, where drying too fast can disrupt the flow or cause unwanted textures in the paint.
However, with slower drying comes a downside: it can mess with the timing of your glazing techniques.
If you plan to build up multiple layers, you might find yourself waiting longer than anticipated for the paint to dry enough for the next layer.
This can affect your overall workflow, especially if you’re used to faster drying time manipulation.
One of the most significant pitfalls is overworking the paint. With more time to blend, it’s easy to keep going and accidentally muddy your colors, especially in areas where you want staining colors to stay vibrant.
Too much manipulation of the same area can also cause the paper texture to break down, especially on more delicate hot-pressed paper surfaces.
Watercolor Surface Preparation Grounds
Watercolor grounds allow you to paint on surfaces other than traditional watercolor paper.
By applying a ground, you can turn almost any surface—canvas, wood, even metal—into something suitable for watercolor painting.
These grounds create a porous texture similar to cold-pressed paper, providing enough tooth for the paint to grip while maintaining the water-based pigments’ natural flow and transparency.
The application is straightforward: you brush the ground onto your chosen surface in an even layer, allowing it to dry thoroughly.
Once set, it behaves similarly to traditional watercolor surfaces, but with added versatility for mixed-media projects.
You can apply watercolor washes, use granulation mediums, and even experiment with wet-on-wet techniques without worrying about the paint sliding off or pooling in unwanted areas.
However, using watercolor grounds isn’t without challenges. If not applied evenly, they can create unwanted texture or bumps, leading to uneven paint distribution.
This can be especially frustrating if you’re trying to achieve smooth glazing techniques or subtle transitions in color mixing.
Plus, grounds can sometimes dry too slick, especially on hot-pressed paper, causing the paint to lift too easily, which makes layering difficult.
One pitfall to watch out for is the drying time—grounds take longer to cure than regular gesso or acrylic primers.
Applying paint too soon could ruin both the ground and the layers of watercolor on top, leaving you with an unpredictable mess.
Practical Tips for Using Watercolor Mediums

Start with gum arabic when you’re aiming for smooth washes and want to control the transparency of your watercolor layers.
It’s excellent for achieving that delicate balance between fluidity and pigment saturation, without the risk of over-diluting. Just don’t go overboard—too much gum arabic, and suddenly everything dries sticky.
If you’re working with granulation mediums, always test it first. Not every pigment responds the same.
You’ll notice some colors granulate beautifully, giving you those textured effects, while others just fall flat. Keep an eye on how it interacts with pigment suspension, especially on different types of watercolor paper.
Blending mediums are lifesavers if you struggle with fast-drying paints. They extend the drying time, letting you focus on those complex color mixing transitions without racing against the clock.
But here’s a tip: use it sparingly. A little goes a long way. If you overdo it, you’ll be left waiting for what feels like forever before you can add any new layers, which can interrupt your entire workflow.
Ox gall is your go-to when you want to enhance paint flow. It’s perfect for wet-on-wet techniques where you need the paint to spread smoothly without abrupt stops. But remember, it can be unpredictable.
Too much ox gall, and the paint might start to behave unpredictably, especially on more absorbent papers like cold-pressed paper.
If you’re experimenting with more experimental mediums like iridescent or thickening mediums, test, test, test.
Don’t assume it’ll work the same way every time. These are great for adding texture or shine, but they can easily overwhelm the transparent watercolor effect you’re likely aiming for. Especially when you start layering—some of these mediums can create unintended opacity.
One more thing: always prep your surfaces properly if you’re using watercolor grounds. Uneven application can lead to blotchy washes and inconsistent texture.
It’s tempting to rush, but trust me, it’s not worth the hassle later when your pigment lifting goes haywire because the ground wasn’t even.
FAQ on Watercolor Mediums
What is a watercolor medium?
A watercolor medium is an additive mixed with watercolor paints to modify their behavior on watercolor paper.
These mediums can affect drying time, paint flow, pigment transparency, and even the texture of the paint, allowing for more control and experimentation in your painting techniques.
How do you use gum arabic in watercolor painting?
Gum arabic is mixed directly with your water-based pigments to enhance the paint texture and increase transparency.
It slows down drying, making it easier to create smooth watercolor washes and delicate color mixing. Use small amounts to avoid sticky finishes and overly glossy effects.
What is ox gall used for in watercolor?
Ox gall improves the paint flow by reducing surface tension. It allows watercolor layers to spread more smoothly, which is particularly useful for wet-on-wet techniques or covering large areas without streaks.
Be careful, though—too much ox gall can lead to unwanted bleeding or difficulty controlling the paint.
What is a granulation medium?
A granulation medium creates textured, granular effects by causing the pigments to clump together on the surface of the paper.
This medium is ideal for adding texture and interest to your watercolor washes or highlighting granulating pigments. It works best on rough or cold-pressed paper.
Can you mix different watercolor mediums?
Yes, you can mix different watercolor mediums to achieve specific effects. For example, using both gum arabic and a blending medium can give you more time to work on complex color layering techniques.
Just be cautious—combining too many mediums can make the paint harder to control.
How do blending mediums affect drying time?
Blending mediums are used to slow down the drying time of watercolor, giving you more time to manipulate the paint.
This can help with color mixing and layering techniques, but if used excessively, it can prolong drying too much, leading to smudging and unwanted color bleeding.
What are texture mediums for watercolor?
Texture mediums thicken the paint or create texture by adding physical dimension to your watercolor layers.
This can be useful for creating detailed textures, like rough surfaces or abstract effects. Granulation mediums and thickening mediums are common choices when seeking more control over pigment suspension.
How does iridescent medium work in watercolor?
Iridescent mediums add a metallic or pearlescent sheen to your watercolors. You can mix them directly with the paint or apply them as a top layer.
These mediums are great for highlights and reflective surfaces, but too much can overpower the delicate transparency of water-based pigments.
How do lifting preparation mediums help?
Lifting preparation mediums prevent colors from staining the paper, making it easier to remove or lift paint once it has dried.
Apply the medium before painting. It creates a barrier, making it possible to lighten areas or fix mistakes without damaging the watercolor paper.
Are watercolor grounds necessary for non-paper surfaces?
Yes, if you want to use watercolor on surfaces like canvas or wood, you’ll need to apply a watercolor ground.
This creates a suitable surface for the water-based pigments to adhere to, allowing for traditional watercolor techniques like washes and layering without the paint simply sliding off.
Conclusion
Watercolor mediums offer a range of tools to customize your approach to watercolor painting.
Whether you’re using gum arabic to enhance pigment transparency, granulation mediums for texture, or blending mediums to extend drying time, each medium opens new possibilities.
These additives help control everything from paint flow to how the pigments interact with the surface, giving you flexibility in techniques like wet-on-wet, glazing, and color mixing.
Incorporating the right mediums into your workflow can improve both precision and creativity.
The key is to understand how each one works and avoid overuse, which can lead to unpredictable results.
By mastering these watercolor mediums, you’ll be able to elevate your work, create more dynamic effects, and gain better control over the final outcome.