Not Marten but Frederik van Valckenborch

Ursula Nusser, from Germany, sells on 20 September 2016 an "Atributed to Martin van Valckenborch" Masked ball, estimated at 1,000 Euro.

This fairly unusual subject is absent from the works of Marten van Valckenborch, but is a few times painted by Frederic van Valckenborch though. He was the son of Marten and is not a very important painter, but this is an agreeable painting with an attractive estimate.

Most of his works feature more figures and life, but the style seems comparable. The above is from the RKD, from an art dealer in Oegstgeest, the Netherlands.