I have a Durst M300 enlarger that has a built-in red filter to allow you to focus on the paper, and a split red - green filter. I think that the split red - green filter might be some kind of a focusing aid, but darned if I can figure out how it works. Can anyone enlighten me?
Here is a link to an online user manual. Pages 13 and 14 explain how it works
Thanks Phill, great site. I never would have figured that out on my own.