A recording sheet comprising a sheet of paper and porous particles provided on the paper surface, said porous particles having an average pore size of from 10 to 5000 .ANG., a pore volume of from 0.05 to 3.0 cc/g and an average particle size of from 0.1 to 50 .mu.m....http://www.google.de/patents/US4780356?utm_source=gb-gplus-sharePatent US4780356 - Recording sheet
