The method for producing a porous film of the present invention includes producing a stretched film by stretching a resin sheet containing at least polyolefin, and then irradiating the stretched film with a vacuum ultraviolet ray. A crude cumene feed stream containing up to 10% AMS by weight is supplied to the first reaction zone 112 and mixed with hydrogen in a first catalyst bed 118 containing a nickel catalyst, converting from 70 to 95 percent of the AMS to cumene. Oxidation is performed to form thicker or thinner oxide portions on the exposed portions of the first and second structures relative to unexposed portions of the first and second structures. The filter filters the channel estimates from the multiplier.