Quote Originally Posted by HalifaxJ View Post
What is the red filter on the enlarger for?
You can position a sheet of B&W paper under the enlarger without exposing it that way. Personally, I only do this with small test strips, to be sure I get them where I want them. With full prints, I position my easel using regular light from the enlarger and a dummy sheet of paper (the back of an old print that didn't come out right).