Winsor & Newton Permanent Masking Medium was designed to, as its name suggests, mask areas of paper and make them water-resistant. It can be applied directly to clean paper, to dried washes on the paper or mixed with watercolours first. When dry, the medium will repel superimposed washes.

If you’ve never used permanent masking fluid before, it might not seem intuitive to use a mask that cannot be removed. But permanent masking fluid is a fascinating medium that is well worth discovering.

Unlike Art Masking Fluid, Permanent Masking Medium is not removable, however, it can be mixed with watercolours before applying them to the paper, making for an interesting coloured effect.

In terms of texture, it paints on a little bit smoother than most removable masking fluids, which can be somewhat rubbery. When dried, permanent masking fluid is much smoother than removable masking fluid.

Important information:

How does permanent masking medium differ from Art Masking Fluid?  

• Permanent Masking Medium is not removable
• Permanent Masking Medium can be added to the colour
• Brushes are easier to clean
• Art Masking Fluid is recommended for crisp whites, larger areas of masking and is faster drying whilst Permanent Masking Medium is recommended for fine detail and expressive effects within the painting.

How is it used?

Permanent Masking Medium can be applied directly to the white paper, to dried washes on the paper or mixed with watercolours first. All watercolour washes mixed with Permanent Masking Medium remain open and workable whilst the wash is still wet. Once dry, the area becomes isolated and cannot be fully penetrated by further washes. A hairdryer can be used to speed the drying. Brushes should be washed in warm water and soap before using other colours.

• Shake the bottle first. The mixture can settle, so be sure to give your bottle a vigorous shake before opening and using.
• Don’t use your best brushes. While you can wash your brushes after using them, the stickiness of permanent masking fluid can have a permanent effect on bristles, dulling the edges and making them stick.
• Let the fluid dry, but don’t wait too long. Like with removable masking fluid, you want to let permanent masking fluid dry before you start any over-painting techniques. But don’t let it dry too long. The texture will change over time, so a wash applied over a recently dried layer of permanent masking fluid will lie differently than over masking fluid applied several days ago.
• Excellent for detail.
• Apply directly to the paper or tint with small amounts of watercolour.
• Allow drying completely before overpainting.

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