Once the shirts have been printed they must be cured and inspected. The dryer consists of a conveyor belt that runs the shirts through a heated chamber. The dryer must be set to the proper temperature and the speed of the belt must be adjusted to insure the required exposure to the heat for complete ink fusion. This is not as difficult as nuclear fusion but must be diligently controlled to insure that the print is durable. Shirts also must be inspected as they are placed on the dryer belt and as they are removed by the folders. Inspection can be problematic if production speeds are high and there is a shortage of personnel. If a printing problem is not caught until the end of the dryer there can be a dozen or more shirts ruined. Unlike other print procedures, the substrate in this process comprises the majority of the cost, so mistakes such as these can be quite expensive. This is why adequate color balanced lighting in all production areas is a necessary to achieve high quality, consistent printing.