Lemon yellow can refer to quite a few different pigments, both historical and modern. We included this as its own entry as sometimes art history books will mention lemon yellow without giving a description of the pigments. In truth it could refer to any yellow pigment or blend, particularly ones that are green-leaning or fairly pale. According to Cameo, a common blend was made of toxic yellow chromates, PY31, PY32 and zinc white.
Field wrote in the late 19th century that the name Lemon Yellow referred to paints made of chromate of barium. At that time he cautioned that if they are not made well they may lack stability.
