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The transport rate of liquid water, i.e., the water penetration rate, into paper is one of the important physical properties in the printing, coating, and gluing processes. However, some kinds of paper are too thin to permit the measurement of the penetration rate in the direction of the thickness accurately. Thus, a novel method for measurement of the penetration rate has been developed. The large difference in electrostatic capacitance between soaked and dry paper and that in penetration rate between filter and thin paper were utilized as the foundation for this method. The time required for penetration through the whole sheet of thin paper was calculated from the measured penetration curve on the basis of theoretical analysis. As a result of the measurements in a relative humidity range of 40 to 70% it was concluded that this method could be useful in the characterization of thin paper materials with respect to penetration. [ABSTRACT FROM AUTHOR]