His technique was described by contemporaries as cursive and almost disdainful in its certainty. He avoided the smooth finishes of his peers, instead using a loose-woven brushwork that sometimes left the grey ground of the canvas visible between strokes. This method allowed him to record the energy of a scene without resorting to theatrical arrangements. His work often depicts figures entirely absorbed in their tasks, such as workers in a foundry or a man walking with his hands behind his back, completely oblivious to the observer.

Modern collectors value Menzel for his rejection of false seduction and artifice. His paintings do not try to flatter the viewer or present an idealised version of the world. Instead, they offer a direct encounter with reality, capturing the physical weight of a body or the specific light of a factory floor. These prints suit contemporary interiors because they provide a sense of honesty and quiet observation.