Slate Photo Plaque: CO2 Walkthrough

A 6×8" slate plaque with engraved photo portrait. Memorial / pet portrait product. Realistic retail: $110-160 single-piece premium (memorial pricing supports the higher end), or $75-95 budget version with reduced setup/finish time. Total time: ~25 minutes engrave + 15 minutes finishing on the premium path.

The order

"Pet memorial plaque with our dog's photo + name + dates. Slate, 6×8" approximate."

Materials

• 1× 6×8" slate piece ($4-12 from craft suppliers or kitchen-supply)
• Soft brush for ash removal
• Microfiber cloth for cleaning
• Sealant (optional): outdoor stone sealer, mineral oil

Step 1: receive customer photo

1. Ask for high-resolution source. Minimum: 600 DPI at final 6×8" = 3600×4800 pixels.
2. Photo of the pet with clear face, good lighting in original.
3. Coach the customer if photo is too small / dark / blurry.

Step 2: image prep (Photoshop / GIMP)

Slate is a "white-on-dark" engrave material, the laser ablates the dark slate surface to expose lighter mineral underneath, leaving a white/gray mark wherever it fires. Light areas in your source image become bright white marks; dark areas stay as untouched dark slate. So the source photo's tonal mapping translates directly to the engrave.

1. Open photo. Convert to grayscale (Image → Mode → Grayscale).
2. Crop to fit 6×8" portrait orientation. Focus on face / subject.
3. Levels (Ctrl+L): drag black point and white point inward to anchor pure 0 and 255.
4. Brightness/contrast: bump contrast +20.
5. Curves: shift midtones DARKER slightly. Reason: full-power laser hits on slate can crack or flake the surface, especially on harder slates. Darkening midtones means fewer pixels get full power, reducing the heat-shock area. Trade-off: midtone detail compresses slightly. Start with -10 to -15 on the midtone slider; tune from there.
6. Unsharp mask: radius 2-3px, amount 50-80%.
7. Resize to 6×8" at 423 DPI (line interval 0.06mm).
8. Save as PNG.

Step 3: design Lightburn project

1. Workspace: 6×8" / 152×203mm.
2. Place tool-layer rectangle for the slate boundary.
3. Drop in the prepped photo. Position centered, leave 15mm margin.
4. Image layer mode: Image → dither: Jarvis.
5. Below the photo: text layer for pet name (e.g., "Buddy").
6. Below that: dates ("2010, 2025") in smaller text.
7. Optional: small paw print clipart at bottom.

Step 4: customer proof

1. Export Lightburn preview as image (Alt+P → Save Image).
2. Email the proof. Especially important on photos, manage expectations on what the engrave will look like (it won't be a glossy print).
3. Wait for approval.

Step 5: prepare slate

1. Wipe slate with isopropyl alcohol to remove dust + oils.
2. Place on bed. Use risers if your bed allows (lifts off honeycomb for cleaner engrave).
3. Verify slate is flat, natural slate may have slight curvature. If significantly bowed, return to supplier.

Step 6: focus and frame

1. Auto-focus or manually set Z to 2" lens focal distance on slate surface.
2. Hit Frame (F4), verify the design lands within the slate bounds.
3. Adjust position if needed.

Step 7: layer settings (35-50W RF tube, 2" lens)

Layer	Mode	Settings
Tool layer (boundary)	Output OFF	,
Photo	Image (Jarvis dither)	Speed 300 mm/s, Power 25%, Interval 0.06mm, Air assist minimum (just enough to keep dust off the lens)
Text (name)	Fill	Speed 350, Power 30%, Interval 0.06mm
Dates / paw print	Fill	Speed 400, Power 28%

Step 8: run engrave

1. Open Preview (Alt+P), verify time estimate (~20-25 min).
2. Press Start. Watch first 30 seconds for unusual sparks or fume flares.
3. Engrave runs.

Step 9: post-process

1. Wait for fume extraction to clear (~60s).
2. Open lid. Brush slate with soft brush, removes loose ash and powder.
3. Wipe surface with damp microfiber cloth. The white mark areas tighten as they dry.
4. Inspect under daylight LED. Photo should have good contrast, recognizable subject, smooth gradients.

Step 10: optional finishing

• Outdoor stone sealer (Tenax, AquaMix), for memorial pieces displayed outdoors. Spray, let dry, light second coat.
• Mineral oil: slight color enhancement; brings out the slate's natural depth. Wipe lightly.
• Skip finishing for indoor display pieces.

Step 11: package

1. Photograph in good light for portfolio (daylight LED, slight angle to catch detail).
2. Wrap in tissue paper.
3. Place in rigid corrugated mailer (8.5×10.5×1" minimum).
4. Add hand-written note (especially important for memorial pieces).
5. Ship via tracked / insured shipping.

Pricing breakdown

Material (slate)	$8
Image prep (Photoshop)	15 min × $80/hr = $20
Setup + proof	15 min × $80/hr = $20
Engrave time	22 min × $80/hr = $30
Finishing	10 min × $80/hr = $13
Packaging	10 min × $80/hr = $13
Total cost (premium path)	$104
Markup (memorial pricing supports premium)	$26-56
Customer price (premium)	$130-160
Budget path (reduced image prep + simpler setup, ~$53 cost)	sells $75-95

Common pitfalls

• Photo looks "muddy" or low contrast: source levels weren't stretched. Re-prep in Photoshop.
• Slate cracks during engraving: power too high or material brittleness. Drop power 5%; pre-warm slate to room temp.
• White mark areas inconsistent: surface dust or oils. Wipe with IPA before engraving.
• Photo hard to recognize from across a room: close-up + cropping helps. Coach customer to send tighter crop.
• Customer wants "perfect like a print": manage expectations. Engraved photos have a different aesthetic than prints. Show samples upfront.