[5] On 1 November 2008, Tummers became the curator of old masters at the Frans Hals Museum in Haarlem, succeeding Pieter Biesboer.
[7] Tummers is noted for her work in developing new methodologies in art authentication, combining traditional connoisseurship with modern scientific techniques.
[8] Tummers’s research often focuses on the ethical dimensions of art authentication, examining the profound impact that expert opinions can have on the cultural and economic value of artworks.
[9] Tummers's work in art historical research has been described by Myrthe Timmers as being different, "from traditional expertise by using the newest technical analysis methods and computer science.
Her European Research Council-funded project has been particularly influential, advancing the field of forgery detection while shedding light on the historical art market and the evolution of artistic techniques, alongside others: Tummers has curated and contributed to several exhibitions at the Frans Hals Museum, including: