Opening a film canister is not difficult. But you should be prepared to do so in the dark or in special lighting. Opening a film canister in the daylight, room light or anywhere that your film can be exposed can ruin your film or alter the images to be developed. If you are not prepared to develop the film once you open the canister there is little reason to open it, and you should simply leave the film in the canister.
Prepare developing area with the materials and chemicals you will need to develop your film.
Have special lighting to avoid exposing your film. Lighting equipment and bulbs can be purchased at a camera store or online supplier. Or you can simply open the canister in the dark.
Position the film canister. The film canister itself holds no special significance for the development of the film. It is merely a protective covering designed to hold the film in a light-free environment until it can be developed. Some canisters are designed to be reusable and are simpler to open. Most are not. The canister is designed with two ends that have spindle-advancement access. One end has a slot and the other the spindle knob. Turn the canister so the end with the knob is sticking up.
Pry the canister open. This end of the canister will have a metal ridge or lip (generally black). Using your fingers (particularly if this is a reusable canister) or your prying tool (bottle opener), pry along this ridge until it separates from the body of the canister.
Remove the film. After the end of the canister is loose, the film will easily slide out of the canister on the spindle and should be placed in the development tank immediately.
Wear white lint-free gloves when removing film from the canister, or at least minimise finger contact with the film. Film should only be handled on its edges.
What may appear to be a dark room may have sufficient light to expose your film. You should take precautions to block windows, doors and other sources of light with heavy fabric before opening the canister.