Engraving anodized aluminum with a laser

Anodizing grows a thin oxide layer on aluminum, and for colored parts that layer holds the dye. The laser does not have to cut into the metal: it removes or bleaches the dyed layer, and the lighter aluminum shows through. On dark — especially black — anodizing, that gives a bright mark with high contrast. Fiber lasers are the standard for metal marking, but CO2 and many diode lasers also mark anodized aluminum, because only the coating has to react. Bare, uncoated aluminum is a different job.

• The laser changes the dyed layer, not the metal
• Dark anodizing → light mark, strong contrast
• Fiber, CO2 and many diode lasers can mark it

Logos, text and line art only need two states — coating removed or not — so they come out crisp when the edges are clean. Photos are harder for two reasons. The coating is thin, so there is little room for shades from power alone; most people use a dot pattern (dithering) instead of grayscale power. And on dark anodizing the engraved parts are the light parts, so the image logic is the reverse of engraving wood. A portrait prepared for birch will look wrong on black aluminum.

• Logos: clean edges, two states
• Photos: thin coating, dot patterns over grayscale
• Light marks on dark metal reverse the image logic

Photo Studio has a material profile for anodized aluminum that sets starting values for brightness, contrast and gamma and suggests the Jarvis dot pattern; you can switch to any of the ten dithering methods and compare in the preview. The Invert control swaps light and dark when your mark comes out lighter than the surface. For logos, the vectorizer and the contour tool turn artwork into clean SVG outlines, and the background remover isolates a product or a pet before the photo work starts.

• Anodized aluminum profile with starting values
• Ten dithering methods, Invert, live preview
• Vectorize and contour for crisp logos

There is no universal speed and power for anodized aluminum: the dye, the thickness and quality of the coating, the laser type and the lens all change the result. Engrave a material test grid — a matrix of speed and power fields — on a scrap piece of the same stock, pick the field that removes the coating cleanly without dulling the metal, and save it as your recipe. Engrave the photo once normal and once inverted on the scrap too; the better one tells you which way your anodizing behaves.

• No universal numbers — the coating decides
• Test grid on scrap from the same stock
• Test the photo normal and inverted

Red, blue, gold or silver anodizing gives less contrast than black, because the exposed metal is closer to the surface color. Logos still read well; photos lose detail faster. Preview with the profile, keep the image simple, and test on the same color before the customer piece.