The invention provides a method for pleating a filtration material (1), having at least one filtration layer (2) and a stiffening layer (4), comprising preparing the filtration layer (2) as a non-woven layer of synthetic fibers, preparing the stiffening support layer (4) as a non-woven layer of synthetic fibers, with a majority of the fibers having an average denier at least two times the average denier of the synthetic fibers of the filtration layer (2) and sufficient in number and denier so that when attached to the filtration layer (2) produces a self-supporting composite (5), forming lines (7) of spaced apart perforations (6) in the support layer (4) with the lines (7) corresponding to intended folds (121) in a pleated filtration material (120), attaching the perforated support layer (4) to the filtration layer (2) to form the composite (5) thereof, and pleating the composite filtration material (5) by folding the composite filtration material (5) along the lines (7) of the perforations (6) in the support layer (4). A corresponding filtration material and framed filter are also provided.