Bridget Riley's discussion of her works from the early 1980s applies to this gouache completed in 1985:

In the paintings I did in the early Eighties, after my visit to Egypt, I chose long thin vertical stripes, because they have very little body and are mostly 'edges'. The interaction between colours is most intense when one colours borders on another. The long edges of the stripes maximise this relationship. When placed vertically the colour event is seen as a horizontal spread of coloured light...

It's...as though the colour is breathing, giving off a subtly tinted cloud of its own transfrmed energy. It happens all the time in nature, but it comes to its own in painting: there colour is at its purest.

(Bridget Riley from The Experience of Painting, Talking to Mel Gooding (1988) in The Eye's Mind: Bridget Riley Colelcted Writings 1965-1999, Robert Kudielka, Thames & Hudson, London, 1999, p. 127)