The application of patina to bronze sculptures represents a crucial final step in metal artistry, with hand-applied and sprayed techniques offering distinct aesthetic results. Hand-applied patinas involve the artist manually brushing or rubbing chemical solutions onto the heated metal surface, allowing for precise control over color gradation and texture. This traditional method creates organic, uneven finishes that highlight the sculpture's three-dimensional qualities, often resulting in deeper, more nuanced coloration that reveals the artist's personal touch.

Sprayed patinas, by contrast, utilize airbrushes or spray bottles to apply solutions in fine mists across the surface. This contemporary approach produces more uniform coverage with smoother transitions between colors, ideal for achieving consistent industrial finishes or subtle tonal variations. While faster to apply, sprayed patinas may lack the tactile depth and artisan character of hand-worked surfaces.

The choice between methods depends on artistic intent - hand application excels for expressive, textural works where brushstrokes become part of the visual narrative, while spraying suits pieces requiring flawless gradients or reproduction consistency. Chemical reactions also differ; hand methods allow for layered, controlled oxidation while spraying often produces more immediate, surface-level effects. Both techniques can be combined, with artists frequently using spraying for base coats followed by hand detailing for accentuation of features.