At a studio party in 1909, Hjertén met her future husband, twenty-year-old Isaac Grünewald, who had already studied one year with Henri Matisse in Paris.

In that respect her work is more closely related to the German Expressionists, such as Ernst Ludwig Kirchner, than to the French painters, with their graceful play of lines.

During this decade, Hjertén created many paintings with indoor pictures and views from her home, first at Kornhamnstorg Square and later at Katarinavägen Street, in Stockholm.

Hjertén sits on the sofa between two artists – her husband, Isaac Grünewald, and, perhaps, Einar Jolin – who talk to each other over her head.

In the foreground a woman dressed in black – a sophisticated alter ego – leans against a male figure who might be the artist Nils Dardel.

Ateljéinterior and Den röda rullgardinen (The Red Blind), from 1916, are daring paintings that have given rise in recent years to new interpretations based on contemporary gender studies and reveal information about the artist's private life.

She recovered periodically, and in the following two years (1932–1934) Hjertén's artistry culminated in a crescendo, where, like one possessed, she made pictures that expressed strongly loaded feelings.

She devoted herself to intensive painting, creating one picture a day, the picture-book of her life, according to an interview in the Swedish art magazine Paletten.

Yet, most contemporary critics had a negative and even scornful attitude towards Hjertén's works of art, and many of them wrote deeply offensive reviews.

"After viewing the nearly 500 works in her 1936 retrospective, the critics were unanimous: the exhibition was hailed as one of the most remarkable of the season and Hjerten was honored as one of Sweden's greatest and most original modern artists.

In the late 1930s, Hjertén was diagnosed with schizophrenia, and was permanently hospitalised at Beckomberga Psychiatric Hospital in Stockholm, where she remained for the rest of her life.

Her paintings seem extremely personal for the era in which they were made, when issues of colour and form were uppermost in artists' minds.