Oh that's lovely! I don't know why digital cameras have such a difficult time with blues and purples! I've found a few tricks to fix the problem .. but it doesn't always work. I always have camera set to bracket exposure .. it automatically takes 3 pictures with different exposure values. I've also noticed that if I set the Exposure mode to center or spot I get truer colors .. Also if I fiddle around with different White Balances that sometimes works .. especially with purples .. I set it to Cloudy and the purples will sometimes come true. If I set it to Incandescent the blues seem to come true. It also depend upon the ambient light as to which setting works best .. on average if I see the camera is having problems I'll change the settings a number of times to different settings and usually one is pretty close on.
The picture below was set on Cloudy with Center Mode ... you can see the difference also the camera was set to Exposure Bracket (Click on the picture to see the 3 different shots).
