How do artists achieve color variations on aluminum figurative sculptures without paint?

Artists achieve vibrant color variations on aluminum figurative sculptures without paint through innovative metalworking techniques. One common method is anodizing, an electrochemical process that creates a porous oxide layer on the aluminum surface, allowing for dye absorption and permanent coloration. Another approach involves chemical patinas, where artists apply specific compounds to induce controlled oxidation, resulting in rich, organic hues. Heat treatment can also produce dramatic color shifts, as the metal's surface reacts to temperature changes with iridescent effects. Some artists use abrasive techniques like sanding or brushing to create contrasting textures that catch light differently. These paint-free methods not only preserve the metal's natural qualities but often enhance durability, making the artwork resistant to weathering while maintaining its visual impact.