The Spectrum paintings of 1983, Moving Colours were on a two dimensional plane. In that year Rokus started with his three-dimensional spectral paintings Moving Colours.
There is an initial plan for a painting. The implementation starts a process in which colour, size and shape influence each other while the final product is not yet determined.
Both changing of colours and moving them over a three-dimensional shape, create new and surprising colour contrasts.
Light and shade also play an important role.
While making the Moving Colours paintings, Rokus has done much research on the clarity/purity of the paint colours. During this research, he went back to only a few pure basic pigments. The result of thus mixed colours are clear, matching colour harmonies.
"The colours are the starting point, call it the music score. They determine the interaction of the notes. The music is a game you always play within grammatical studies. It is the surprise of what is happening, where the critical eye thereon determines the result and the next step."