1986 - 2003 working in Pattaya under contract of different art studios. The last 10 years only for the Suwit Gallery in the Royal Garden Shopping Center.
Becoming famous for his exact and sensible kind of painting, Dumrong was often requested for from customers not knowing his name, but remembering his dark skin colour, as "the black artist". This is the reason why Dumrong started to sign his commissioned works with the name "Black".