In addition to her arduous day jobs, Louis painted by candlelight, largely in secret isolation, until her considerable body of work was discovered in 1912 by German art collector
Wilhelm Uhde. While in Senlis, Uhde saw a still-life of apples at his neighbor's house and was astonished to learn that Louis, his housecleaner, was the artist. His support had barely begun to lift her horizons when he was forced to leave France in August 1914; the war between France and Germany had made him an unwelcome outsider in Senlis. They only re-established contact in 1927 when Uhde – back in France and living in
Chantilly – visited an exhibition of local artists in Senlis and, seeing Louis's work, realized that she had survived and her art had flourished. Under Uhde's patronage, Louis began painting large canvases, some of them two meters high, and she achieved prominence as an artist. In 1929, Uhde organized an exhibition, "Painters of the Sacred Heart," that featured Louis's art, launching her into a period of financial success she had never known – and was ill prepared to manage. Then, in 1930, with the effects of the
Great Depression destroying the finances of her patrons, Uhde had no choice but to stop buying her paintings. ==Death==