Thanks so much for the reply. The 6100 is calibrated, and is using the same paper and settings as always. There have been no new software updates (I'm running the latest firmware), and the ink cartridges associated with purples are all reletively full. I've had experiences where entire photos were discolored, but in this case everything else looks sharp and vibrant except for purples.
Although the ink cartridges aren't low, is it possible that it could be a problem with a cartridge? When you say hardware failure, is it possible that some component of the printer could fail and cause this issue. The 6100 is a little over three years old, if that helps.
Also, could a nozzle clog cause this kind of problem? I did one nozzle cleaning, but is it possible that multiple cleanings could be required?
Again, thank you for taking the time