>The older units have filters that slide behind the lens. While this >is a better place for the filter, nobody makes filters for the >enlareger that fit the slot.(posted 8563 days ago)Au contraire. There are loads of Polycontrast filters, as well as Ilford filters, and others out there which are easily used in that slot. Also, they have a black filter holder into which you can insert your own gelatine filter.