Measuring liquid penetration in the thickness direction of paper T. Karppinen, I. Kassamakov, J. Aaltonen, H. Pajari and E. Hæggström Eur. Phys. J. Appl. Phys., 32 1 (2005) 65-71 Published online: 25 October 2005 DOI: 10.1051/epjap:2005071