No records exist which would indicate when Tiffany started creating enamel pieces in the EL series. It is believed, however, that these works were executed shortly after he began producing enamelware around 1898. Those pieces marked EL are noted for their experimental nature, and their scale, coloration and forms vary dramatically from those works marked SG. According to art historian Janet Zapata, EL may possibly stand for experimental. Of the 90 or so enamels Tiffany retained for his private collection, approximately 65 were from the EL series.