Dithering converts a grayscale photo into a binary (black/white) pattern that simulates continuous tone when engraved. The algorithm you choose dramatically affects the result — especially on different materials. Reticle Red's Photo Prep tool includes all five major algorithms.
Floyd-Steinberg The standard. Distributes quantization error to neighboring pixels, producing a natural grain pattern. Works well on: wood, leather, MDF. Avoid on: acrylic (error diffusion shows as blotchy).
*Best for: portraits on wood, general photo engraving.*
Stucki Similar to Floyd-Steinberg but spreads error over a larger neighborhood, producing a smoother result with finer grain. Slightly more processing time.
*Best for: fine-detail portraits, high-DPI engravings on maple or cherry.*
Jarvis-Judice-Ninke Largest error diffusion kernel of the three. Produces the smoothest gradients but can lose fine edge detail. Good on large-format pieces where you're viewing from a distance.
*Best for: large wooden signs, slate tiles.*
Bayer (Ordered Dithering) A grid-based pattern that creates a regular halftone look. No error diffusion — deterministic output. Produces a "screen-printed" aesthetic rather than photorealistic.
*Best for: graphic/pop-art style portraits, logos with gradient fills, anodized aluminum.*
Atkinson Developed for early Mac printing. Spreads only 75% of the error, causing it to preserve highlights and drop shadows — creating a high-contrast, punchy look.
*Best for: dark materials (slate, dark walnut), images with strong contrast, where shadow detail is less important than bright areas.*
Quick reference: - Natural portrait on wood → Floyd-Steinberg at 254 DPI - Sharp detail, light wood → Stucki at 300 DPI - Graphic/stylized look → Bayer at 200–254 DPI - Dark slate or stone → Atkinson at 254 DPI - Large format sign → Jarvis at 150–200 DPI
Always run a 50×50mm test patch before committing a full piece.