Extreme Drawing

Crayon resist for kids: the wax and watercolour trick

Art technique

Paint over it and the hidden drawing appears

Draw with crayon, then paint watercolour over the top. The paint soaks into the bare paper but beads up on the crayon, because wax repels water. A white crayon drawing stays invisible until the paint reveals it, like a secret message.

Play in your browserDo it for real
  • Ages 3+
  • 20 minutes
  • Low mess
Painted illustration of the painter brushing blue watercolour over paper, revealing a white crayon fish and bubbles.

Quick facts

Age
3+
Time
20 minutes
Mess
Low
Adult needed
Only to set out the water and paints
You need (cost)
Wax crayons (with a white one), watercolours, paper: cheap
On screen / for real
Both

What you'll make

A painting with crayon lines that shine through the paint: fish under a blue sea, a spider’s web on a dark night, or a secret message that only appears when someone paints over it. It is the same technique as wax resist, and Dutch and Flemish classrooms know it as wasco en ecoline, after a wax crayon and a liquid watercolour.

In Extreme Drawing

  1. Crayon (drawing bar): draw with any colour. The White crayon is there for exactly this: a nearly invisible wax drawing.

  2. Watercolour (drawing bar): paint over it. The paint beads up on the wax and hardly takes, so the crayon lines show through and the white drawing appears.

  3. Other wet things over crayon: Ink drops (Craft) are held off the wax too; Water drops are turned away by the waxed fibres; and Bleach drops (Bathroom) fade the colour around a crayon line but not under it.

  4. Time → Bake in the oven. The crayon melts into the paper in smooth, deep colour, and the paper goes slightly see-through where the wax soaked in.

Also try: soap resist. A drop of Dish soap (Science) leaves soap in the paper that watercolour avoids, just like wax. Coloured pencils hold a little wax too, so they resist a little. All of this is free; the bar of soap (Bathroom) is in the full toolbox.

Play in your browser
Painted illustration of the painter brushing a rainbow watercolour that bleeds into wet paper, with crayons, markers, a paint box and a child's rainbow drawing.

For real

Do it for real

You need

  • White paper, the thicker the better (cartridge or watercolour paper)

  • Wax crayons, including a white one (oil pastels work too)

  • Watercolours or liquid watercolour, mixed watery

  • A big soft brush, a jar of water and some kitchen paper

Step by step

  1. Draw with crayon

    Press hard: a thick layer of wax resists best. Light, scratchy lines let some paint through.

  2. Hide a secret

    Draw or write something with the white crayon. Look at it from the side: you’ll only see a faint shine.

  3. Mix runny paint

    Watery paint works far better than thick paint, which simply covers the wax.

  4. Paint over everything

    Sweep the brush across the whole page. Don’t scrub over the crayon.

  5. Watch it appear

    The paint pulls back from the wax and the drawing pops out. Dab beads of paint off the crayon with kitchen paper.

  6. Dry it flat

    Leave it to dry flat; heavy paper buckles less.

Variations to try

Secret messages

Write a note in white crayon and hand it to a friend with a brush. The words appear as they paint.

Autumn spider webs

White-crayon webs and leaves under a dark wash: the autumn classic in Dutch schools, often made into paper lanterns.

Halloween night

Ghosts, bats and a moon in white and yellow crayon, then a deep purple or black wash.

Under the sea

Fish, shells and bubbles in bright crayon under a blue-green wash.

In the app vs on paper

On screen

The paint beads up on every crayon fibre, every time. You can also show what water and bleach do to crayon, and bake the page to melt the wax into the paper. Everything for this technique is free.

On real paper

How well it resists depends on how hard you pressed and how watery the paint is. Beads of paint sit on the wax and need dabbing off. Very wet paper buckles, and a heavy sheet helps.

Painted illustration of the painter brushing blue watercolour over paper, revealing a white crayon fish and bubbles.

Why the paint slides off the crayon

Crayons are made of wax, and wax and water don’t mix. The watery paint slides off the wax and soaks into the paper around it, so the drawing stays bright.

For grown-ups. Paraffin wax is hydrophobic (water-repelling): water’s surface tension stops it wetting the waxed fibres, so watercolour beads up and runs off onto the bare, absorbent paper. A heavy wax layer seals the fibres; light strokes only coat the raised tooth of the paper, so paint gets into the valleys between. The same principle is behind batik (hot wax on fabric) and decorated pysanky eggs, and soap in the paper resists for a similar reason.

Try next: what do you predict?

Pencil or crayon?

Does a coloured pencil resist paint as well as a crayon?

Thick paint?

What happens if you use thick poster paint instead of watercolour?

A candle?

Does rubbing an unlit candle on paper work like a white crayon?

Hard or light?

Which secret message shows up better: one pressed hard or one drawn lightly?

For teachers

In the classroom

Crayon resist fits KS1 Year 1 everyday materials (describing materials as waterproof or not) and NGSS 2-PS1-1 (classifying materials by their properties). It makes a good first investigation: which drawing materials let water through, and which keep it out?

Ideas for teachersUsing it on the whiteboard

Questions parents ask

Why isn’t my crayon resist working?

Press harder with the crayon and use runnier paint. Thin crayon lines and thick paint are the usual reasons the drawing disappears.

What is the difference between crayon resist and wax resist?

There isn’t one: crayons are wax, so crayon resist is a kind of wax resist. Candles, oil pastels and white wax crayons all work.

What paint is best for crayon resist?

Watercolour, liquid watercolour or very watery poster paint. Thick paint covers the wax instead of sliding off it.

What is “wasco en ecoline”?

It is what Dutch and Flemish schools call this technique: drawing with wax crayon and painting over it with liquid watercolour, named after two well-known products. It is the same wax resist.

How do you write a secret message with a white crayon?

Write it on white paper with a white crayon, pressing hard. Give it to a friend with a brush and some watercolour: when they paint over it, the words appear.

Try these next

Painted illustration of the painter pointing at a golden-brown heart and star that appeared on paper after ironing, with an iron, half a lemon and a cotton bud.

Invisible ink

Secret writing in lemon juice that turns brown with heat.

Painted illustration of the painter scratching through black paint with a wooden stick to reveal a rainbow rocket, planets and stars.

Scratch art

The same wax under black paint, scratched with a toothpick.

Hide a white-crayon drawing on screen

Draw with the white crayon, paint over it and watch it appear. Then bake it and see the wax melt into the paper.

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