Parafilm And Waxfilm

Cut Parafilm: First of all you need to cut your parafilm to the required size. It has been conveniently marked out so you just have to follow the blue lines. We are going to go two squares across like so.

Remove Backing And Fold: I like to take the film, remove the backing, and fold it in half along the long edge like this.

Wrap Petridish: Now we are ready to take our petri dish and start wrapping the film around. Be concious of what you have inside your dish as you probably want to keep the dish flat while wrapping it up so the contents don't go everywhere. The film stretches so if you start by pinning the end down with your left thumb you can pinch it with the thumb and forefinger of your other hand so the tips of your thumbs are touching, and then pull it about 3-4cm while wrapping it around the agar plate. You can definitely over stretch it and it will snap so err on the side of caution. Stretch, attach, stretch, attach, going all the way around the rim of your agar plate. Think of it like stretchy clingfilm.

Seal Petridish: Once you get all the way around there is usually a small overlap which is ideal for making sure the dish is completely sealed and also indicates you are stretching the parafilm the right amount.