As I had a few last minute Christmas cards to make I returned to a technique which is quick and easy and I think effective also perfect for a OLC. Firstly I stamped the background using an acrylic block, I inked the block with Distress Ink tumbled glass and spritzed with water then stamp onto the card, depending how much water you spray depends on the effect you get, also any dye based ink works I've found. My first card is the one I'm entering into the challenge and has been spritzed quite heavily making a very subtle water effect background, the second picture shows different effects with less spritzing.
These cards show the effects with less spritzing
Hope all your Christmas preparations are going well
bye for now

