A method for processing a heat-sensitive positive-working lithographic printing plate material is disclosed which comprises at least two layers: —a first layer comprising an oleophilic resin and/or a vinyl acetal (co)polymer; —a second layer comprising a (co)polymer which is located between the support and the first layer; comprising the steps of: —treating the plate material with an alkaline development solution, —treating the plate material with a first gum solution and consecutively with a second gum solution which are configured as a cascade whereby the second gum solution overflows into the first gum solution; and which gum solutions include a buffer; characterized in that the pH of the first gum solution reaches a steady state value above the pKa value of the (co)polymer present in the second layer.

A problem to be addressed by the present invention is to provide a method of producing a printed material by printing an active energy ray-curable printing ink on a film, wherein the printed material has good adhesion between the ink and the film even after undergoing boiling treatment for boiling sterilization or retorting sterilization. Such a problem is solved by a method of producing a printed material, including the steps of printing an ink on a film; and irradiating the ink-printed face with an active energy ray; wherein the film contains: a polyamide film layer; and a layer that, as the outermost layer of at least one face of the film, contains a polyurethane obtained by use of a polycarbonate polyol as a polyol component.

Provided are a positive type planographic printing plate precursor including: a support which has a hydrophilic surface; and an image recording layer on the support, the image recording layer containing: a polymer compound 1 having at least one bond selected from the group consisting of a urea bond, a urethane bond, and a carbonate bond in a main chain and containing a sulfonamide group in the main chain; a polymer compound 2-1 having at least one of a constitutional unit represented by Formula S-1 or a constitutional unit represented by Formula S-2 or a polymer compound 2-2 having a constitutional unit represented by Formula EV-1 and a constitutional unit represented by Formula EV-2; and an infrared absorbent, and a method of producing a planographic printing plate obtained by using the positive type planographic printing plate precursor.

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Provided are: a positive type photosensitive resin composition including a polyester containing a sulfonamide group in a main chain thereof, and an infrared absorbent; a positive type planographic printing plate precursor obtained by using the positive type photosensitive resin composition; and a method of producing a planographic printing plate.