In case you were wondering, we used freezer paper to create stencils for painting our t-shirts. Freezer paper is a wide, white paper sold in the U.S that has a thin plasticy coating on one side. It is wide enough to cover the front of a medium sized adult t-shirt easily. Larger areas need to be pieced. I don't know if you can get it in the U.K., but I have seen others say they couldn't get it in AU. (If you know one way or the other, please leave me a comment and let me know.) If you can't get freezer paper, I think contact paper will work just as well, maybe better. Just more expensive. Though contact paper may allow you to use your stencil more than once. Hum...
1) Wash your shirt and dry it without any fabric softener or dryer sheet.
2) Draw or print your stencil on the paper side of the freezer paper. Yup, I use my ink jet printer. Just make sure you print on the paper side. I found the Tardis stencil online, several months ago. I've uploaded the file to my flicker account. You can download it here.
Don't remember where, but it was attached to a tutorial on how to make a Tardis t-shirt. If you know, please leave me a comment and I will post a link.
3) Cut out your stencil. I use my handy xacto knife. Scissors are not really good for this.
4) Lay the paper pieces on your fabric, plasticy side down, and iron them into place. Use the hottest setting your fabric will allow. Check and make sure your paper is stuck to the fabric, especially little pieces.
5) You are now ready to paint. A sponge type brush works best because you want to dab on the paint, not brush it on, or it will seep under the stencil. And less is more here.
6) Remove the stencil, VERY CAREFULLY! Removing the stencil is best done when the paint is wet, so the paint doesn't pull off with the stencil. Just be very careful not to smear the paint. If the paint does dry,which it almost always does for me, just go slowly and try to hold the paint edge in place as you pull. I've found pulling parallel to an paint edge is best. Also, I tend to cut away sections of the stencil as I go to make removal easier, and for me, more successful. I have heard of people removing the stencils whole and using them again. I'm just not that good.
And when you are done, you should have something like this