Bronze patinas offer a unique way to enhance metal surfaces, but the application method significantly impacts the final result. Hand-applied patinas involve manually brushing, spraying, or rubbing solutions onto the bronze surface, allowing for precise artistic control. This technique creates organic, nuanced color variations and subtle textures that reflect the artisan's touch. Common hand-applied patina solutions include ferric nitrate for reddish-brown tones and cupric nitrate for greens and blues.

Chemically induced patinas, by contrast, rely on accelerated oxidation processes through immersion or exposure to reactive gases. These industrial methods produce consistent, uniform finishes quickly but lack the artistic variability of manual techniques. Chemical patinas often penetrate deeper into the metal, creating more durable surfaces ideal for architectural applications. Ammonium sulfide solutions create dark brown to black finishes, while potassium sulfide produces antique green effects.

The choice between methods depends on project requirements. Hand techniques excel for artistic pieces where visual complexity matters, while chemical processes suit large-scale production needing uniform durability. Both approaches require proper surface preparation and sealing to preserve the patina's appearance over time. Understanding these differences helps metalworkers select the optimal approach for their specific bronze finishing needs.