The elastic energy stored in a double-edged notched tension specimen at the moment of crack propagation initiation is analysed. The stored energy increases linearly with specimen length and, in the range of interest, almost linearly with crack length. Experiments show somewhat surprisingly that copy paper specimen dimensions contribute to the external fracture work very much according to the linear elastic analysis. The specific essential fracture work of such a material cannot be determined as proposed by Cotterell and Reddel, this obviously applying to most paper grades. The fracture work of extremely tough and ductile sack paper appears to be independent of specimen dimensions as long as the sample is not longer than its width.