How to Use Masking Fluid (Watercolor for Beginners)

One of the frustrating things about painting with watercolors is that once you paint a dark color you can’t paint a lighter one on top.

Well, what if you could preserve the lighter areas before you add the dark hues?

That is why in this post you will learn all about how to use masking fluid for your watercolor paintings so you can do just that!

Let’s get started…

What is Masking fluid?

In watercolor painting, masking fluid is a liquid that when applied to paper, can be used to preserve small areas, usually the lighter values, of a painting. For example, if you’re painting snowcapped mountains or water reflections it can help preserve the highlights.

How to use masking fluid

To use masking fluid, you simply have to apply it to the areas you wish to preserve. Next, allow it to dry then paint over it like normal. After the paint has dried, gently rub the dried fluid with your hands to remove it.

Here’s the process in detail:

1. Planning your painting

Before you begin painting, you first need to know what areas you wish to preserve. Creating a value sketch can make a huge difference with this step. Draw the general outline of your painting using a pencil. 

Note down where the lightest areas will be, that’s where you’ll want to apply the masking fluid.

2. How to apply it

For this step, you’ll need a brush. Never use a good-quality brush with masking fluid because it will get ruined!

If you don’t have a spare brush, you can also use the end of a brush handle or a toothpick. 

With your brush apply the masking fluid on the areas you marked in your sketch. Once you finish, close the bottle tightly and let the paper dry. Rinse your brush with water, however, don’t use the same water to paint with.

Before you begin painting, make sure the masking fluid has completely dried. You’ll be able to tell that it’s dry once it becomes rubbery. 

After it has dried you can paint over it and finish your painting like normal. 

How to use masking fluid step by step

3. How to remove the masking fluid

To remove the masking fluid, the paper must be completely dried. This is because if the paper is still wet, you could end up ripping it. 

You can remove it by hand or using different tools such as a rubber cement eraser. Most artists just use their hands by gently rubbing them on the paper to remove it. Remember not to use too much pressure or go too quickly as this could cause the paper to rip.

NOTE: Never leave masking fluid longer than two days otherwise it can become very hard and rip the paper when removing it. If you plan on finishing your work another day, it’s best to remove it and then reapply it the next time you work on it.

How to remove masking fluid

4. Soften and blend

Once you remove the fluid you may notice sharp edges, for this reason, you may want to soften some of them. You can do this by re-wetting the edges with a damp brush and lifting the pigment or blending it.

How to use masking fluid wet on wet

Another way to create softer edges is by applying the masking fluid on wet paper. Here’s how:

  1.  Wet the paper with clean water, you don’t want to dilute the fluid too much so don’t over-wet the paper.
  2. Dab the masking fluid into the area you want to preserve and allow it to dry.
  3. Finish the rest of the painting and wait for it to dry
  4. Remove the fluid and finish up the painting

 This technique can be very handy for negative painting. The images below shows each step:
how to use masking fluid wet on wet step 1
Using masking fluid wet on wet step 2

Different types of fluid

Masking fluid comes in different colors such as blue. This is to help the artist see where they’ve applied it in their painting. In addition to that you can also purchase it in different forms: bottled and marker pens.

While marker pens are more convenient for quick work and your brushes stay safe, bottled versions allow for more flexibility. Marker pens are also great for beginners while bottled versions require a touch more experience. 

At the end of the day, it all comes down to personal preference. I prefer to use the bottled versions however, you can have both.

Maskin Fluid Techniques to Try

Below are a few techniques you can practice with or use in your watercolor paintings.

Painting water

Being able to preserve the reflective areas when painting lakes, rivers, and waterfalls makes everything so much easier. To use this technique, apply the fluid onto the paper where the reflections are. Paint over it starting with a light blue and then dropping in some dark blue. 

The images below show a rough example of using this technique:


You can use a toothbrush or paintbrush to splatter small dots across the sky of your painting to create galaxy paintings or a night sky. Heres how to splatter:

Splattering with masking fluid
How to splatter with masking fluid step 2


You can mask the areas of your painting after adding the first layer. Simply wait for it to dry then apply the fluid like normal.

Extra Tips and FAQ

Always change the water

Once you’ve applied the fluid and cleaned your brush make sure to clean out your jar and fill it with clean water. You don’t want to use the same water to create your painting.

Can you use masking fluid on painted areas?

You can use mask areas on already painted layers, provided that the previous layer has dried and that you don’t leave it for too long. If you plan on not working on your painting for days on end, remove then reapply it.

Is it okay to use a hair dryer?

Using a hair dryer or any heat tool may cause the dried masking fluid to stick to the paper and become very difficult to remove.

Can you mix masking fluid with water?

You can mix the masking fluid with a few drops of water to make it easier to spread and apply. However, adding too much water will make your painting chalky and the masking fluid will no longer be water-resistant.

Are there alternatives to masking fluid?

There are some alternatives you can try including wax resist, oil pastel, masking tape, lifting, and, blotting. Learn more about the other options in this article: 8 Excellent alternatives to Masking Fluid

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