After the dry film is applied to the copper layer, it can be etched. There is an option to use ferric chloride (FeCl3), but it can not be reutilised and needs to be disposed.
Being able to make your own printed circuits boards is a skill that can come in handy. There are several ways to do this and I will describe the one that I use. First part of the process is the creation of a layer on top of the copper that prevents the solvent to dissolve it.
During the process of manufacturing of home-brew PCBs you need to expose the photosensitive film with ultraviolet light. A cheap and low power solution can be found in UV led strips.