12 Tips for Using Masking Fluid in Watercolor Painting

Masking fluid, also known as liquid frisket, is a very handy tool for fine art watercolorists to preserve white areas that would be too tiny or complex to paint around.

What is masking fluid, exactly? It’s made of a suspension of latex in water and is usually lightly tinted to make it easier to see on the paper, either a light yellow or gray. Ammonia is added as a preservative.

Glass Container with masking fluid, beside paint brushMasking fluid, I did pour a small quantity in a container so the fluid in the bottle wouldn’t dry. 

Here are some tips for using masking fluid:

1. Before using masking fluid you need to have your painting all planned so you know exactly where the highlights or areas you will want to preserve are.

Tiny areas in this painting are preserved with masking fluid.Tiny areas in this painting are preserved with masking fluid.

2. Never shake the bottle, as it will cause the product to lump and you might get tiny air bubbles in the fluid. You can stir it gently.

Rubbing a brush on a bar of soap to clean Rubbing a brush on a bar of soap before painting with masking fluid.

3. Use an old brush or a cheap plastic brush to apply masking fluid, as it would ruin a nice expensive one. The brush will be easier to wash if you rub it before on a bar of soap with a bit of water. Silicone brushes (Colour Shapers) are also very convenient for smaller areas, as you only need to wait for the masking fluid to dry and then peel it off the brush. You can also splatter masking fluid with a toothbrush or draw lines with a toothpick or a squeeze bottle with a fine tip.

applying masking fluid to watercolor paper with a silicone color shaper
Applying masking fluid with a silicone brush (Colour Shaper)

4. It is possible to add a bit of water to masking fluid to make it easier to apply, but adding too much water will make it loose its resisting properties and adhere too strongly to the paper.

5. If using a brush, clean it as soon as possible. Masking fluid dries quickly and becomes more difficult to remove.

6. It is possible to apply masking fluid on an area that has been previously painted, just know that when removed, the latex will probably pick up some of the color underneath and make that area lighter.

7. Change you water before starting to paint as the latex will make the colors appear dull.

removing masking fluid by pulling gently with fingersRemoving masking fluid by pulling gently with your fingers

8. Wait for the masking fluid to be thoroughly dry before starting to paint, otherwise it might mix with your paint. Unfortunately, you can’t save time by using a hair dryer, as the heat will make the latex adhere to the paper and it will be very difficult to take off. Exposure to full sun or high temperatures will have the same effect.

9. If left for too long on a painting, masking fluid might become almost impossible to remove. The time you can safely keep the masking fluid on the paper depends on a number of factors, including the brand, external temperature, expiration date, etc.

10. When the painting is completely dry, you can either use a soft eraser, a rubber pick up tool, or just peel it off the fluid by pulling it gently. You can pass your hand slowly on the paper to detect any small area of masking fluid you did forget to take off.

"Out of the blue" watercolor painting by Sandrine Pelissier

“Out of the Blue” by Sandrine Pelissier. The tiny white areas were preserved with masking fluid.

11. Masking fluid works very well to preserve white areas on your paper, but these areas tend to have a very hard (sharp) edge that could lend to an unnatural look on your painting, almost like a decoupage look.  A good way to prevent this is to soften the edges with a stiff brush and water.

12. You don’t need to preserve all white areas with masking fluid — sometimes it’s easier to just paint around it if the shape is quite simple.

Do you have a tip for using masking fluid that you would like to share?

27 Comments

Angie

Wonderful information. I had never heard of this product and looking forward to giving it a try and seeing the results. Thanks for posting.

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Sandrine

Yes it can but won’t give as crisp a result as gutta, outliner and wax. I am using masking fluid on canvas as well when I paint with watercolor and liquid acrylic.

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Gary Cadwallader

You can clean your brushes with Goo Gone. Then wash with soap and water and it’ll save a brush that you thought was ruined by the masking fluid.

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Barb Gilley

I chip off a piece of plastic spoon to apply masking fluid in a flowing manner. Dip it in the masking fluid, and drag it along the paper.

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Dianne

If you count to 20 then rinse your brush between applications it helps prevent your brush from clogging up and ruining it, just don’t count too slow.

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Cyndy

I use various sizes of found sticks instead of brushes. They can be cleaned and sharpened and after use the masking fluid rolls right off.

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Isabella Rolandini

I also add watercolor to my pen and inks, but I use contact/rubber cement to mask the paper . I believe its less expensive (4.00) and works just as well in the same manner. I don’t add water to it.

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Maria Garcia ----Portugal

This method really helps me to preserve the blanks of paper I don’t want to colour .It’s good for lights of water-colour paintings. Thank you

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Eduardo Hernandez

I sometimes apply masking fluid with one of those soft rubber-pointed brushes that some people use for oil painting. Any dry masking fluid that remains on the brush after use can then be easily removed, and the brush is never ruined. They are more versatile than sticks or toothpicks for applying the mask.

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Mary Pat Nash

Very well done. Lately I switched from using soap to protect the brush to Masque Cleaner made by Richeson Mediums. It protects the brush and cleans off the masking fluid afterwards. “Out of the Blue” is beautiful!

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T Dee

Thank you for this write-up, the painting example and all the comments. Masking fluid is a great tool but also fairly expensive so must be preserved. I have used the masking pen and a couple bottles of fluid that are now dried up, as well as masking tape. I am curious about rubber cement, white wax crayon or any other methods that artists use to reserve white or lighter areas.

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Carol Allen

Yes, I have used white crayon, but it is very difficult to see it on the paper. If you tilt the paper then you can see where it is because it catches the light. Crayons have great control, they don’t dry up and you can lightly run them over the paper and to let some of the paint reach the paper in a textured way. However you can’t remove the wax. so you are stuck with it being white, even if you change your mind. PS you can also use colored crayons for a different effect.

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Carol Allen

Yes, I have used white crayon, but it is very difficult to see it on the paper. If you tilt the paper then you can see where it is because it catches the light. Crayons have great control, they don’t dry up and you can lightly run them over the paper and to let some of the paint reach the paper in a textured way. However you can’t remove the wax. so you are stuck with it being white, even if you change your mind. PS you can also use colored crayons for a different effect.

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Frederick Olmsted

My images are from photography meeting watercolor and then adding watercolor after printed on watercolor paper. I’m excited to try either cement or masking fluid.

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Sandrine Pelissier

Your technique sounds very interesting, let me know how masking fluid works with it:)

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Tracy

Sadly, if you are allergic to latex this is most probably a product to keep away from….however, I am sure there must be some alternatives? :-)

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Katelyn

I have a problem with my masking fluid, I follow all of the tips correctly but when I attempt to peel the masking fluid off after i paint on it and it dries, the paper comes up with it and rips. How can I prevent this from happening?

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Dot

Masking fluid mustn’t be left on for days or left in the heat or it won’t come off without tearing the paper.

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Lyn R

the quality of the paper you use is important ,both when using masking fluid or tape . You will not have a problem removing either if you use 100 percent cotton rag paper.
Also masking fluid is affected by light . I decant a small amount ,into an air tight jar and keep the bottle wrapped in foil in the cupboard . It is very irritating to have to throw away a half used bottle which has turned to glug!

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Tom Herrin

Good advise. I like all of your posts. I always get it right on the second try.

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Kate B

On location, though, masking fluid applied in this way takes far too long to dry. A trick to preserve small areas of white I learned from Cathy Johnson (of Artists Journal Workshop). She uses wax paper! Put the wax side down and draw in pencil, pressing a bit, the area which is to be preserved. I also just learned of this pen, which dries very quickly and is now the only masking fluid I use on location: MOLOTOW™ GRAFX Art Masking Liquid Pen. It comes in 2mm and 4mm sizes. The 2mm is refillable.

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Alison

Another tip is to store the bottle upside down. That way the thinner, easier to apply mask, is at the top and the thicker, gunkier mask goes to the bottom of the bottle.

Reply

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