Olive Harbutt, the daughter of of William Harbutt's (inventor of plasticine) was an inspirational plasticine painter. Her paintings would have made great plasticine paint by numbers kits. https://www.instructables.com/id/How-to-make-your-own-Van-Gogh-paint-by-numbers-Pai/

One of my favourite book illustrators Barbara Reid also inspired this Playdough Painting class for children. Why not play dough I thought. Here's the result of a short session with mushy playdough. Even the mum's and dad's had a go. I kept the playdough in an uneven marbly state which added a rather nice subtle effect to the paintings.

Step 1: Recipe for Playdough Paintings

The playdough recipe used here was:
2 cups plain flour
2 cups water
1 tbl tartaric acid (kills bacteria and adds bounce)
2 tsp teatree oil / orange oil
1/2 cup salt
(For mushy playdough added 1/2 cup of water extra)

Step 2: Mixing and Colouring Playdough

Mix all ingredients in a large pot or double boiler, whisking in blender first to break up large lumps.

Cook at medium heat until mixture forms a ball. If too sticky, keep on cooking, it should take around 10 minutes to reach a good state - usually having a springy texture. Let cool a few minutes on a plate. While still warm, don a pair of gloves and knead thoroughly.

For colouring your playdough, add small drops off food colouring with satay stick and knead thoroughly.

Step 3: Plan Your Picture

Roughly sketch your image or decide what colours you want to use. Make the primary colours - both cool and warm versions of each to create 1000 colours.

I used food colouring to colour the playdough as I find the colours are rich and blend quickly compared to using acrylic paints.

Rather than thoroughly kneading to blend colours evenly I kept the playdough in an uneven marbly state which added a rather nice subtle effect to the playdough paintings.

Step 4: Playdough Painting Techniques

The painters used toothpicks, paddle pop sticks, fingers and plastic wrap to create textural effects. We found that the sticky playdough stuck to everything but pressing the surface onto the cardboard with plastic wrap worked effectively to keep the playdough easier to manage.

Step 5: Textural Effects

Here the young artist used her fingers to press the soft playdough onto the cardboard surface. She mixed the colours to create lovely textural effects for her underwater scene.

The next playdough painter used plastic clingwrap for softer textural effects.

Step 6: Effects of Drying Playdough

After one week the playdough tends to dry to a white crusty layer.

The whole painting solidifies as the water evaporates and hardens. This results in a durable rock-like picture.

Because playdough paintings are dry after a couple weeks easily to a durable hard surface, it might be possible to experiment with using playdough to make your moulds for modeling in air dry clays such as cold porcelain clay.

It becomes quite heavy and can be painted with a layer of mixed pva paint and water to restore the colours to their original brightness.

I tried another experimental mix - using cold porcelain clay mixed with playdough mixture minus tartaric acid. The results was a cream coloured soft dough that dried over a week in the sun rock hard over a chicken wire armature for a small diorama.

Step 7: Improved Recipe

Recipe 2 Experimental

I'm experimenting with an additional ingredient which I used in my plasticine recipe to improve my playdough recipe to make waterproof items.

Recently, I checked my mushy playdough mixtures and added a ratio of 1:1 calcium hydrated lime to each colour. Some of them remain mushy while other colours dried to a smooth, solid very tough material. I'll return the mushy mixes to the stove and dry them out further, to reach the almost authentic playdough recipe.

NB. ("Lime is an alkaline substance and therefore, caustic. You need to wear gloves, long sleeves, and eye protection to avoid the possibility of lime burns." - Janine Bjornson (Green Home Natural Building Plaster)