"Layering a vivid orange across an arsenic green, crouched under a line of cobalt, sends messages to the brain; and those messages can be communicated, however inadequately, in language.
...dark greens, particularly dappled with apple greens, and strong verticals may produce a feeling of security in a hominid species that emerged relatively recently from the protection of forests.
Hodgkins uses colour in ways that may be at times highly personal and autobiographical but are more often in a long tradition, fully alive today."
- from this piece by Andrew Marr on the artist Howard Hodgkin, essential reading for anyone interested in the visceral power of colour combinations and why they affect us in that way
P.S.: The Howard Hodgkin page on Artsy.net is a brilliant resource.