Between 1858 and 1861 he stayed in Paris where he studied at the workshop of the Swiss painter Charles Gleyre at the École nationale supérieure des Beaux-Arts.
[3] The theme of Catholic clergy was popular at the time as evidenced by the vogue of cardinal paintings made by artists such as the Belgian Georges Croegaert.
[6] Hermans joined the Société Libre des Beaux-Arts, founded in Brussels on 1 March 1868, which brought together several famous Belgian naturalist artists such as Charles de Groux, Alfred Verwee, Constantin Meunier, Louis Dubois, Félicien Rops, Constantin Meunier, Louis Artan de Saint-Martin and Théodore Baron.
The members admired the work of the French Realist painter Gustave Courbet and wished to confront the prevailing Academism in contemporary Belgian art.
The battle with the Belgian art establishment appeared to have been won when in 1875 Hermans' At dawn was accepted at the Brussels salon without opposition.
[2] Hermans participated in major international exhibitions such as the art section of the World Fair held in Paris in 1878 where he showed At dawn to general acclaim.
He had hoped to reiterate the reception of At dawn by creating the large, ambitious work The masked ball, which was exhibited at the Paris Salon of 1880.
The composition shows a large room filled with groups of partygoers some of whom are in the shadows looking from a balcony in the background while others are active on the crowded dance floor in the front.
A new high point of this period is the composition Circe as temptress, which shows a seductive woman in a modern interior with a man passed out at a table with an overturned wine glass.
[3] Hermans' large-format Realist works were influential on the next generation of Belgian artists such as Eugène Laermans and Léon Frédéric.