Tilliard worked primarily in copperplate engraving. He avoided the soft styles of his contemporaries. Instead, he preferred a sharp and technical approach. His prints of sculptures and classical ruins rely on precise cross-hatching to define volume. This method allowed him to translate the heavy stone of a tomb or the texture of a bas-relief into a two-dimensional medium. His plates for the Voyage pittoresque de la France show this mastery of light and shadow through line alone.

Modern collectors value Tilliard for his architectural rigour. His prints function as both art and historical documents. The monochromatic nature of his engravings makes them easy to place in contemporary rooms. They provide a sense of order and permanence. A Tilliard print offers a connection to the classical tradition without visual clutter.