The varying color tones in Paul Klee's "Ancient Sound" were intended to be associated with music.
Paul Klee is an abstract artist whose works are influenced by cubism, surrealism and expressionism. Aside from being an artist, he is also a musician, a violinist. In fact, before painting, he would play violin as his warm-up. This is why the color tones in his artwork express the connection to music.
To be good at art and know what you are going to paint and have oil paint
Da Vinci - Renaissance
Blake- Romanticism
Cimabue- Late medieval
Pontormo- Renaissance
... from my memory. Sorry if Pontormo is wrong.