A process for producing paper or board, which process comprises ad-mixing (I) an aqueous composition of pH ≦6 and (II) at least one water-soluble polymeric anionic compound to a paper stock having a pH in the range from 6 to 8 and then dewatering the paper stock by sheet formation and drying, wherein the aqueous composition comprises (a) polymers having primary amino groups and/or amidine groups to a combined content for these groups of ≧1.5 meq/g of polymer, and (b) 0.01 to 50 mol % of 1,4-cyclohexanedione (b) based on the combined amount of primary amino groups and/or amidine groups of the polymers, and also to the paper or board thus obtained.