The present relates to a nanoporous carbon membrane manufacturing method comprising coating a block copolymer film with hydrophilic and hydrophobic blocks, on a sacrificial non-porous substrate so as to prepare an block copolymer film coated foil, transferring the block copolymer film on a porous support, pyrolizing the block copolymer film to form a nanoporous carbon film, wherein the transfer step consists in a wet-transfer process comprising placing the block copolymer film coated foil in an etchant bath in an etching chamber and the porous support above the height of said etching bath, etching the underlying sacrificial foil of block copolymer film coated foil, raising the height of the etching bath above the porous support, bringing the free-floating etched block copolymer film on top of the porous support, and lowering the etching bath height below the porous support so as to deposit the copolymer film on top of the porous support.