Great Colours for Fairisle (NaMoBloPo #2)

I've been collecting cloud pictures for a few years now. They're all in this set on Flickr. My idea, apart from just loving clouds, is that eventually I'll get a shot with the right balance of colours for the *perfect* fairisle jumper. But how to distil the colours from the photo?

There are lots of free tools (and paid for ones) but I've been using a fre…