Spot Size & Resolution
With DithX you prepare images to match your laser: your beam has a physical Spot Size (usually 0.08mm for diode, 0.15mm for CO2).
The Golden Rules of Prep:
- Resolution (DPI) Match: Calculate your DPI based on spot size:
25.4 / Spot Size (mm). For a 0.08mm spot, use 318 DPI. Going higher overlaps lines and creates charring. - Shadow Recovery: Most materials darken significantly when burned. Brighten shadows by 20-30% in your editor to compensate for the laser's physical dot gain.
- Unsharp Masking: Apply aggressive sharpening. The laser beam's "bloom" will soften the final image; "crunchy" pixels on screen result in sharp details on wood.
Start Here: First Steps
New to laser engraving? Avoid the "burned black mess" with these simple starter tips.
1. The Focus Test
Focus is 90% of the battle. Use a "Ramp Test" to find your laser's sweet spot. A tiny focus difference can mean the difference between a sharp photo and a blurry blob.
2. Greyscale vs. Dither
Never use "Greyscale" mode for photos on wood. It's too unpredictable. Always use a Dither algorithm (like Jarvis or Floyd-Steinberg) for consistent results.
3. Small Sample Tests
Don't engrave a 20cm photo as your first test. Create a small (3cm) test patch. Save time, save material, and find your settings faster.
4. Clean Your Lens!
Smoke and sap will coat your laser lens. A dirty lens loses 50% of its power and blurs the beam. Clean it with IPA after every long engraving.
Wood 1: The Borax Hack
The Mixture
- 1 Cup Hot Water
- 1 Tablespoon Borax Powder
Instructions
- Dissolve Borax completely in hot water.
- Sponge onto wood surface (Maple/Birch/Poplar).
- Let dry completely.
- Engrave. The Borax acts as a flux, preventing soot and creating a dark, chocolate-brown mark.
Wood 2: The Kenny Hack
Vinegar-based stain for rich, aged dark burns.
The Brew
- Usage: 50% Cleaning Vinegar
- Reactant: Steel Wool (approx 2x photo size, fine grade)
- Time: Dissolve for ~1.5 weeks in a plastic jar (shake occasionally).
Preparation
- Dissolve steel wool in vinegar until gone. Filter through a coffee filter.
- Top up with 10% Water to dilute slightly. Shake well.
Application
- Coat wood with the mixture. Let dry 24 hours (Wood will discolor/age).
- Optional: Add white watercolor paint for depth, dry 24h, sand with 320 grit.
- Engrave with Lower Power than usual.
Slate: The White Burn
The Reaction
Slate doesn't burn black; it bleaches WHITE.
Instructions
- Pre-Treat: Apply a thin coat of Matte Clear Varnish. This creates a deep black "wet look" base.
- Invert: You MUST invert your photo in software. Black pixels = No Laser. White pixels = Laser fires.
- Clean: Wash with water after engraving to remove dust.
TiO2 Recipe V1 (Alcohol Base)
Ideal for Glass & Ceramic Tiles using Airbrush.
Ingredients
- 3 parts TiO2 (Titanium Dioxide)
- 0.5 part MoS2 (Optional, helps flow)
- 1 drop Glycerin
- 99.9% Isopropyl Alcohol
Instructions
- Mix powders with just enough alcohol to form a thick paste. (Crucial Step!)
- Add 3-4 parts Alcohol to dilute for airbrushing.
- Use an Ultrasonic Cleaner to blend perfectly. Add a small metal ball to the bottle for re-mixing later.
TiO2 Recipe V2 (Water/Glue)
Ingredients
- 2 parts TiO2 (e.g., 50ml)
- 3 parts Water (e.g., 75ml)
- 1.5 parts Wood Glue (e.g., 37.5ml)
Instructions
- Mix all ingredients thoroughly.
- The Wood Glue acts as a strong binder, creating a durable coating on glass or tile for engraving.
- Apply evenly with a sponge or brush.
TiO2 Recipe V3 (Metal Marking)
Permanent black mark on Stainless Steel (RVS) & Brass.
Base Mix
- 5 parts TiO2
- 3 parts MoS2 (+3 extra for Brass)
- 2 parts Graphite
- 7-10 parts Alcohol
- 1 drop Glycerin
Laser Settings (33W Ref)
Slow & Hot: 100mm/min @ 95% Power.
For RVS: 250-350mm/min @ 80% Power.
Result is extremely durable and resistant to steel wool.
Physics Over Magic
Stop guessing. Professional engraving relies on these three critical calculations:
Speed vs. Power
Rule of Thumb: Faster is sharper. Slow speeds cause heat to "soak" into the wood, blurring the dots. Use 80-100% power and find your max speed for the darkest mark.
Line Interval
The distance between horizontal passes. Set this equal to your spot size (e.g., 0.08mm). If it's too small, the wood burns; if it's too large, you see white lines.
Overscan
Essential for preventing dark "soot" marks on the edges. It gives the laser head room to accelerate before it starts firing dots.
Scanning Offset
Compensates for the mechanical delay. If your edges are jagged or "stair-stepped," you need to calibrate your offset values in your controller.
Fixing Common Failures
Banding (stripes)
Usually mechanical. Loose belts or a wobbly Z-axis. Also caused by resonance speeds. Try changing speed by ±10% to move out of the resonance frequency of your frame.
Ghosting / Double Image
Scanning Offset is wrong, or your belts are loose. The laser head is physically jerking when changing direction.
Washed Out / Low Contrast
Too much power (overburn) or the image wasn't processed with enough Gamma/Contrast. Or you're engraving wood that has too much resin (try the Borax trick).