I have made contact sheets of 35mm negs with base exposure of 20.2 seconds @f/11 without Filter. Paper: MCP 312 semi-matte Developer: Adotol NE - 1 min. Enlarger: Focomat Ic. Film: APX 100 and Fomapan 100 developed with Rodinal 1+50. Contact sheets gave an overall idea about the print exposures and as well as neg exposures(APX is lossy compared to Fomapan). Now I am curious about the effect of filters(atleast Grade 3) before I burn some more paper. One thing for sure is it will affect the contrast but I wonder whether it will effect the base exposure too...if so, how much? Provided the height, the lens opening and other variables are kept constant.