This process has become revived recently with the introduction of safer, light-sensitive polymer films and plates adapted from the circuit board industry. The image is generated by exposing a photo positive to a photo polymer plate via a high powered light. Usually, artists need to do extensive testing to determine the exact exposing time for each image. The exposed plate is developed in water and can be printed almost immediately. It is important to understand that photo etchings are not a means of reproducing existing photographs or drawings. Photographs that will become the base for the photo etching usually need to be shot and developed differently than for photographic prints. Equally, for drawing-based photo etchings artists need to create a new drawing on mylar which will become the photo positive. For this drawing, artists need to keep in mind the specifics of the photo etching process (gain of contrast, loss of light grays, etc) just as lithographers who create drawings on plates or stones need to keep in mind the specifics of the lithography process. The advantage of photo etching is its flexibility, which allows artists from varied backgrounds such as photography, computer graphics, and drawing to create hand printed limited editions.