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 15 algorithms across four families — error diffusion, halftone screens, ordered (Bayer) grids, and plain threshold. The five below are the workhorses to learn first.
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 The largest error-diffusion kernel shown here. 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.*
Match image resolution to the physical mark DPI is not free detail. At 254 DPI, pixel spacing is about 0.10 mm; at 300 DPI it is about 0.085 mm. If the focused spot, material response, or line interval cannot reproduce that spacing, extra source pixels merge into heat and mud. Set the final engraving dimensions first, choose a resolution your machine can physically mark, and sharpen only after resizing. The wood settings guide provides starting ranges, but a material test remains mandatory.
Run a controlled comparison Use one representative crop containing a face, a smooth gradient, dark hair or shadow, and a hard edge. Export the same crop with two algorithms while keeping dimensions, DPI, speed, power, focus, and material orientation fixed. Engrave both on the same piece of scrap, label the samples, then change one variable at a time. This separates a dithering decision from a power or focus problem and creates a repeatable shop record instead of a one-off guess. Photo Prep lets you compare the algorithms before export.
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.
Frequently Asked Questions
What is the best dithering algorithm for laser engraving photos on wood?
Floyd-Steinberg is a useful first test for photo engraving on wood, but there is no universal best algorithm. Grain, spot size, line interval, coating, focus, and the source image can outweigh the algorithm choice. Compare Floyd-Steinberg with Stucki on the same crop and matching scrap; try Atkinson when a lighter, higher-contrast result reads better on dark material.
What is Floyd-Steinberg dithering and when should I use it for laser engraving?
Floyd-Steinberg is an error-diffusion dithering algorithm that converts grayscale photos to binary black-and-white by spreading color rounding errors to adjacent pixels. The result simulates continuous tone gradients using a dot pattern that reads as smooth when engraved. Use Floyd-Steinberg for: portraits on wood at 254 DPI, general photo engraving on most natural materials, and any project where photorealistic rendering is more important than graphic style. Avoid it on acrylic — the error diffusion can appear blotchy on hard, reflective materials.
Should I use Bayer or Atkinson dithering for dark materials like slate?
Use Atkinson dithering for dark materials like slate, dark walnut, or dark stone. Atkinson only spreads 75% of the quantization error (instead of 100% like Floyd-Steinberg), which causes it to preserve bright highlight areas and drop shadow detail — giving a high-contrast look that reads well on materials where the engraved area is lighter than the base. Bayer (ordered dithering) produces a regular halftone grid pattern — use it for graphic or pop-art style portraits, logos with gradient fills, and anodized aluminum where the structured pattern is aesthetically desirable.