At one point I tried to use waxed paper but this did not work as well. I only used grocery plastic bags. You could also use the baggies (Ziploc idea), as Alisa did.
I learned a few things while doing this Plastic Bag Printmaking:
Don’t use too much water unless you want a smeared look (and that may be what you want).
Wait a few moments before putting the paper over the wet paint.
Press down when you want the print to look like what you put on the plastic.
Rub back and forth when you want to smear the paint around.
Plastic bag, opened and cut
Open the plastic bag. On the plastic put the paint – in shapes, blobs, lines. You can use one colour at a time; or you can mix them right on the plastic.
Place a piece of watercolour paper over the paint. Press down or rub depending on what type of effect you want. The picture below shows what happens when I rubbed back and forth and the paint was very wet, too. You get a smear of colours.
Repeat as often as you want around your page.
If you want a design as well, get a clean sheet of plastic. I drew on the plastic with pencil, then marked the design I wanted (the sea turtle). Then I traced over the lines in paint. A thinner brush would have given a finer detailed turtle.
The picture below shows both the printed sea turtle design as well as the leaves with drier paint on the plastic, and pressing down and not rubbing.
Finish the picture. I loved how this worked.
Try plastic bag printmaking and tell me how it turned out.
Please check out more about my book Tadeo Turtle on Tadeo’s Page. You will find more activities at the back of my book. And a 24-page extension activities is available if you ask.