Have the colours in this painting faded over the years?
Absolutely. There are a number of Van Gogh's floral works, from Saint-Rémy and Auvers periods in particular, that have faded dramatically over the years. The chemical composition of certain paints that Van Gogh was using wasn't entirely stable and many of the reds and blues have faded to pale whites and greens. We're fortunate to have photographic records, of course, and conservators today are making every effort to stabalize the paintings, but it's still unfortunate that there are some of Van Gogh's paintings we'll never again see as he intended them.