In watercolour painting, unlike other media, the whites are not added as paint but are reserved areas of the paper that are not painted on, so the white is the colour of the paper. Working with Masking Fluid is intended to give you some confidence in using masking fluid to develop your practice.
Masking fluid is a liquid latex-based product (non latex versions are available)
Masking fluid is a liquid latex-based product that is very effective at keeping small areas and thin lines white when painting on watercolour paper. The rubber prevents the paint from reaching the paper and is peeled off to expose the white paper left untouched. Masking fluids come in different tints so you can see where you have painted it.
The places that masking are most useful are small white areas or lines within a large even wash of colour, like sailboat rigging against the sky, where you don’t want to paint around areas and interrupt a smooth wash.
For those of you who react badly with latex Pebeo have produced a range of non latex masking products.
View our masking fluid
View our masking fluid applicators
View our masking fluid remover
Applying your masking fluid
When working with masking fluid it can be applied in many ways, almost any tool will work. You may use a brush, a ruling pen, a dental pick, a Colourshaper applicator or a special fine needle point applicator which is a needle that gives extremely fine lines. If you need splattered white dots you can flick the masking fluid from an old toothbrush.
View our masking fluid applicators
If using a brush you might want to keep one inexpensive brush to use exclusively for masking fluid. The latex might not come out completely when you are finished.
One trick (if using a brush) is to wet the brush thoroughly and wipe the hairs over a bar of soap or dip it into washing up liquid, making sure that the hairs are thoroughly coated right up to the ferrule and then use it to apply the masking fluid. Wash the brush thoroughly immediately after use.
The paper must be dry when you apply the masking fluid. If it is wet the masking fluid will soak deeply into the paper rather than sitting on the surface. The paper will usually tear off with the masking fluid when you attempt to remove it when you are finished. The same problem occurs if you dilute the masking fluid when you use it.
Do Not shake the bottle. Shaking the bottle will introduce air bubbles and if applied the bubbles will pop during drying and leave unprotected spotty areas.
If your masking fluid is too thick you can thin with a few drops of distilled water.
Paint your watercolour (over the masking fluid)
Wait until the masking fluid is completely dry, at least five minutes, before you paint the watercolour. After you have finished your painting and it is completely dry you can then remove the masking fluid.
Remove the masking fluid
Remove the masking fluid as soon as possible after the painting is dry. The longer the mask is left on the paper the more likely it will be to adhere and be harder to remove. Also, the colouring in the tinted fluids can stain the paper if left on for a long time.
Some artists rub with their finger or a putty rubber to get it started, or use a specially designed eraser such as Maskaway.
Get a corner to pull away and then lift this away from the paper. It should pull away in thin stretchy strips or sheets. If you find it hard to get a grip, try easing the dried fluid with the edge of a scalpel. Be careful not to rip the paper.
After you have mastered working with masking fluid you will be rewarded with those lovely sparkling whites in your watercolour paintings. To enhance those whites (or add more) then a tube of White Gouache (an opaque watercolour paint) will be your friend.