Dien specialised in line engraving, a method requiring immense control. His approach involved translating the tonal qualities of paintings into a network of fine lines. In works like Pope Blessing, based on a composition by Raphael, he managed to convey the weight of fabric and the softness of skin using only black ink. This technique allowed him to reproduce masterworks of the High Renaissance for a wider audience while maintaining the formal balance of the original art.

Modern collectors value Dien for the clean, architectural quality of his prints. His work provides a bridge between the classical tradition and the structured aesthetic of nineteenth-century French academia. These engravings function as sophisticated decorative elements that suit minimalist or traditional interiors. Because they are monochromatic, they allow the viewer to appreciate the pure form and composition of the subject without the distraction of colour.