Micro-samples from 57 original paint tubes used between 1904 and 1909 by the Norwegian painter, Harriet Backer were studied with inductively coupled plasma-optical emission spectroscopy (ICP-OES). This accurate elemental characterisation of Backer's original materials aims to fill several gaps in conservation science, painting conservation, and art technology. Firstly, it provides a novel and validated analytical method that can be applied to other painting materials. Secondly, ICP-OES offers scientific information about different oil colours from the late 19th to the early 20th century by Dr. Schoenfeld & Co., Düsseldorf, currently known as Lukas-Nerchau, whose archives were depleted during the Second World War. This work also lends new insights into the paintings of a renowned female Norwegian artist, whose painting materials have been little studied to date. ICP-OES results, coupled with a comprehensive, illustrated catalogue of paint tubes, will be instrumental for ongoing scientific investigations of this painter's body of work.