The filtration characteristics of white water from papermaking has very important property, it's ratio of wet to dry cake mass m and the average specific filtration resistance a(av). This study used Talc and CaCO3 slurry, and the constant pressure filtration experiments done on the filtration pressure and concentration changes. Used sudden reduction effect of filtration area. In this paper showed that investigated to determine specific filtration resistance by filtration experimental under constant pressure. The filtration flow rate was also affected by factors that can be changed on consistency, pressure drop. Results of this experiment, we can see that reduce production costs by recycling the white water and wastewater treatment.