In 1917 the Royal Tropical Institute - then the Colonial Museum - was sent a series of glass negatives with portraits of the employees of the Singkep Tin Company. They were a response to a contest through which the Colonial Museum was seeking to put together a photo show emphasizing the prosperity of the Dutch East Indies. What is exceptional about the photographs is their focus on local employees. Studio portraits in those days were the preserve of the white colonial elite. Native employees were at the most photographed on the work floor or in the fields. It is not known who made the series. Regarding the employees depicted, only their function, and sometimes their ethnic background, is reported. That makes it a contradictory project. On the one hand, the portraits bestow status and respect, on the other they emphasize the archetype just as much as the individual.

The series of portraits of employees of the Singkep Tin Company is part of the collection of KIT (the Royal Tropical Museum) in Amsterdam. The exhibition for which the photographs were submitted was never realized, due to the outbreak of the First World War.