Multiple steps are involved in the manufacturing of polypropylene woven bags. Since polypropylene is a thermoplastic polymer, the first step is to melt the granular polypropylene and pull it into flat threads. During this process color pigment can be added to make bags with other colors than white. High speed circular looms weave the threads to form a continuous tube of woven plastic cloth. The diameter of the tube is determined by the final dimension of the bags. The plastic cloth tube will then be cut to required length and the end sewn to form a bag. To make it waterproof, a thin sprayed-on film can be applied on the woven cloth, or some customers prefer to have an inner bag made of thin film. The bags can be three-color printed or have the full-color print on them. full-color is achieved by preprinting plastic film with full-color plastic printer, and laminating the film on the bag.