Here is another example of using a card design from the catalog and retro fitted it to a set I have and papers I had. The cards I chose are on page 47 of the Stampin Up Spring/Summer collection. (you can check it out by clicking the link to the right with the cover of the catalog)
I happened to have the exact colors of each card. I used the water-coloring technique for both of these. If you notice on the tall card I didn't have any Certainly Celery printed paper, so I made my own with Itty Bitty Backgrounds set and some Whisper White Craft ink.