Vier portretten van een onbekende man, opnames gemaakt met verschillende belichtingen before 1891

"Vier portretten van een onbekende man, opnames gemaakt met verschillende belichtingen" (Four portraits of an unknown man, taken with different lighting) is a photographic work created by Loescher & Petsch before 1891. The work features four portrait photographs of the same man taken with different lighting. This type of image was often used in photographic textbooks and manuals as a demonstration of the different ways that lighting could affect the outcome of a portrait. The work is a valuable document of the photographic practices of the late 19th century.