Roosmarijn is an art historian and archivist in training. At OR else she focuses on project management, organizational advice and advising about art and cultural projects.

She has been commissioned by Paleis Het Loo Het to work on a major renovation and expansion and she also worked at the Stedelijk Museum in Amsterdam on the big revenue exhibition of Kazimir Malevich. In
addition, she advises various museums and cultural institutions on a freelance basis. Before Roosmarijn worked in 2012 on behalf of the Museum de Lakenhal, raising funds for renovation and extension. She is also relationship manager of the Lucas van Leyden Mecenaat, under the chairmanship of Elco Brinkman. In the same year she was committed to the Royal Palace of Amsterdam for the annual summer exhibition.

For her employers and clients she leads project teams on very different levels, working together with curators, artists, boards of directors and voluntary workers. For the smaller projects the responsibilities are also of an executive nature. In addition to her knowledge as an art historian Roosmarijn has an instinct for the human element within a project and enjoys being the connecting factor. She keeps a keen eye on the process and never loses sight of the required objective.

Before joining OR else, in addition to her regular work Roosmarijn also carried out freelance assignments on a regular basis. Among these assignments was one in 2004 in which, in collaboration with artist and artistic adviser Peter van der Heijden, she organised an exhibition in the Hortus Botanicus in which 14 artists gave their vision of nature. She also advised the art commission of CLB/Sanquin on their art collection and in 2007 she realised a temporary museum in Stadsdeel de Baarsjes. Public areas and/or local participation play important roles in many of her projects.

On june 1st, 2018, Roosmarijn took up the post as director of the Regional History Centre Vecht en Venen (RHC). Roosmarijn remains involved with OR else in the background.