J. L. Keffer was active in the 19th Century and worked with the Philadelphia lithographer P. S. Duval in 1839. He also worked with chromolithographer Alphonse Brett around 1846 in the partnership Brett & Keffer, which issued Christmas and Valentine’s Day cards delineated by engraver Nicholson Devereaux, including one held in the collections of the Historical Society of Pennsylvania.  Their partnership dissolved by mutual consent by 1847.