E.C. Kropp was a printer and publisher that began producing chromolithographic souvenir cards and private mailing cards in 1898 under the name Kropp. The E.C. Kropp Company was later founded in 1907 in Milwaukee, Wis., and produced large numbers of national postcards and other subjects. The company’s linen cards had a noticeably fine grain. L.L. Cook purchased the company in 1956 and they are now part of the GAF Corp. U.S.
Source: Metro Postcard