Sonia had used gouache earlier in her career but in the 1950s she embraced the technique with a new energy.

Often in small formats, these gouaches allowed her to test out shapes which she would then transpose onto different supports.

The gouaches show Sonia experimenting with shapes which were characteristic of her paintings of the period, but integrated into a new language of composition and colour which elevates them beyond preparatory sketches to works of art in their own right.