Enlarger Aperture Calculator Aperture and Multigrade filter changes for darkroom prints Fields keep your last setting until this tab is closed. Clear all 01Current print Exposure time Aperture (marked) Filter Paper 02New settings Aperture (marked) Filter Ilford filter factors: grades 00 to 3½ need no change, 4 to 5 need double. 03Result Aperture change Filter change Total change Original exposure Expose for 04Burns and dodges (optional) AreaCurrent timeNew time Add burn or dodge Times accept 1:13, 1:13.5, 1m13s, 1min13sec, 73 or 73s. A bare number is seconds.