I bought some of the Crafter's Workshops stencils recently to use on art journal pages, to make the background on a page. I made two pages quickly with this stencil, just tracing around the stencil with an extra fine black Sharpie. Once I had the outline I colored in the butterflies with several colors pf Sharpie Poster Paint pens. Instant background and very cool looking.
This is a favorite of mine. You get clean images from it. I got the 6x6 but I think I remember it in 12x12 too. The plastic is not cheap and will last for years. It makes a great mask.