His approach relied on precise line work to mimic the textures of velvet and armour. In works like Man in Armor, he used varied hatching techniques to suggest the reflective surface of polished metal. He avoided the loose brushwork popular in his era, preferring the clarity of the engraved line. This method allowed his prints to maintain a sharp definition even when reduced for books or catalogues. He often chose subjects that bridged the gap between contemporary politics and historical drama, such as his depictions of Victor Emmanuel II and Charlotte Corday.

Modern collectors value Metzmacher for his disciplined execution and the formal quality of his portraits. His prints provide a sense of historical weight without the clutter of more ornate styles. The monochromatic nature of his engravings fits well in contemporary interiors that favour a neutral palette. His studies of historical figures offer a window into 19th-century perceptions of power and identity. These works function as quiet, intellectual additions to a gallery wall or a study.