For the rainbow green I had a play with cucumbers. They are not very interesting... but... if you slice them thin enough you can create very cool effects when you lay them on a white screen of, for example, an iPad.
However, all my pictures have black in them and I wanted to keep that look for my calendar. So Photoshop to the rescue... Then suddenly a cool effect appeared and when I was on it, I just had to make the green some what greener...
Now I will think about tomorrows blue... that will be a difficult one...
Very cool!