His technique relied heavily on sanguine, a red earth chalk that allowed for soft transitions and bold outlines. Ango often worked directly in the Musei Capitolini, as seen in his work Artist Sketching in the Musei Capitolini, Rome. He captured the scale of ancient sculptures and the movements of other artists at work. His drawings possess a sketch-like immediacy that prioritises the energy of the line over precise anatomical detail. This approach gives his religious and mythological scenes a sense of motion and spontaneity.

Modern collectors value Ango for the warmth and texture of his medium. Red chalk prints provide a sophisticated alternative to standard black and white sketches. The compositions, such as Christ Washing the Feet of the Apostles or the Massacre of the Innocents, offer a glimpse into the creative process of the Roman art scene. These works suit contemporary spaces that require a balance of classical subject matter and expressive, hand-drawn execution.