What is a focus tool, and why do I need one?
This is a tool which you put under the enlarger, on top of a sheet of paper (used, because you are going to expose it to white light to focus) to help in focusing the enlarger. They have a mirror that reflects the image into an eyepiece. You adjust the focus on the enlarger until you can see the grain clearly. Many people focus without one, I found that having one makes it much easier to focus.
