Heldt was associated with New Objectivity but developed a more melancholic style. He used a limited palette of greys and earthy browns. His compositions often use windows to frame the outside world. In Grand Piano with Window View and Still Life at the Window, he explores the boundary between private and public space. He reduced buildings to basic geometric shapes. This gives his cityscapes a structural, almost rhythmic quality.

These prints appeal to those who value stillness. Heldt avoided the frantic energy of the modern city. He focused on the silence of empty streets and still objects. His work fits well in contemporary homes because of its clean lines and restrained use of colour. Collectors find his blend of architectural precision and surrealist mood provides a calming influence in a room.