The Lumentum Laser Repair Guide: 5 Steps to Prep a Photo for Engraving (And What Most People Get Wrong)

Who This Is For (And When You’ll Need It)

If you’ve ever had a client send you a photo for laser engraving—like for a plaque, a gift, or a memorial piece—and the result came out looking like a muddy blob instead of a crisp image, this is for you. I’ve been in the thick of it, triaging orders for clients who needed everything yesterday. In my role coordinating laser services for industrial and custom fabrication clients, I’ve handled 200+ rush orders in four years, including same-day turnarounds for event companies and corporate gift shops.

Here’s the thing: preparing a photo for laser engraving isn’t complicated, but most people skip the critical steps. This guide covers five steps, and I promise you’ll learn at least one you’re probably not doing (I wasn’t for the first year, and it cost me a $1,200 redo).

Step 1: Start with the Right Resolution (Don’t Trust “High Res”)

When I first started prepping photos for engraving, I assumed “high resolution” on a client’s email meant I was good to go. Not even close. I learned that lesson the hard way when a client sent a “high-res” photo for a 10” x 8” plaque, and it turned out to be 72 DPI (dots per inch). The engraving looked like a pixelated mess.

What to do: For laser engraving, you need at least 300 DPI at the final output size. Here’s a quick check:

• Open the photo in any image editor (I use GIMP because it’s free).
• Go to Image > Print Size (or similar).
• Check the resolution and dimensions.

For a 5” x 7” engraving, you need an image that’s 1500 x 2100 pixels (5 inches x 300 DPI). If it’s anything less, don’t start yet. Either upsample the image (which I’ll cover in Step 3) or ask the client for a better original.

Step 2: Convert to Grayscale (But Don’t Just Click “Grayscale”)

Lasers work by burning the surface. They don’t do colors—only shades of gray matter. A common mistake is converting a color photo to grayscale using the default “Grayscale” mode in Photoshop or something similar. That method flattens the image, losing detail. When I did this in my first year, I submitted a photo for engraving on a Lumentum laser system, and the result had no contrast. It was just a gray square.

What works: Use Image > Mode > Lab Color, then discard the “a” and “b” channels. Keep only the “Lightness” channel. This preserves the tonal range way better. I finally learned this after a $600 redo in March 2024, when a client’s family portrait came out looking washed out. Since then, this is my go-to method.

Step 3: Optimize Contrast (The Step Everyone Skips)

Here’s the secret: even a perfect grayscale image won’t engrave well if it doesn’t have contrast. Lasers need clear separation between light and dark areas. Think of it like a black-and-white movie: if everything is medium gray, you can’t see the actors.

How I do it:

1. Open the image in an editor and adjust the levels (Ctrl+L in GIMP).
2. Slide the dark point to just before the histogram starts (this deepens shadows).
3. Slide the light point to just before the right edge (this brightens highlights).
4. Adjust the midtones slightly—but not too much. You want to add punch, not distort the skin tones.

Last quarter alone, I processed 47 rush orders, and I estimate 30% of the image issues were caused by flat contrast. This step alone can turn a “blob” into a recognizable face.

Step 4: Dither or Halftone (But Know the Difference)

This is where most DIY guides go wrong. You can’t just send a grayscale image to the laser. The laser can’t “see” shades of gray—it’s either on (burns) or off (doesn’t). So you need to translate grayscale into dots.

Two common methods:

• Halftone: Uses dots of varying sizes. Good for photos with smooth gradients (e.g., a sunset).
• Dithering: Uses a pattern of tiny dots. Good for portraits and fine details.

I prefer dithering for portraits. In March 2023, a vendor failure taught me the difference: I used a halftone pattern on a portrait of someone’s dog, and the fur came out as weird circles. The client’s alternative was reprinting the whole thing (a $500 loss).

My setup: In LightBurn (the software I use for Lumentum lasers), I choose Stucki or Floyd-Steinberg dithering for portraits. For landscapes, I use a halftone. It’s not hard-and-fast, but it’s a reliable starting point.

Step 5: Test on a Scrap Piece (Seriously, Do This)

I can’t tell you how many times I’ve skipped this because I was in a rush (unfortunately). In February 2024, I had a rush order for a memorial plaque—a photo of someone’s grandfather—needed in 24 hours. I prepped the file perfectly, or so I thought. But I didn’t test it. The first (and only) engraving turned out fine, but the power setting was slightly too high, and the detail in the eyes was lost. The client was understanding, but it cost us a $250 rush fee to redo.

The rule: Always engrave a test piece. Use the same material, same settings, same everything. Adjust power and speed by 5% increments. For Lumentum systems, I usually start at 80% power, 300 mm/s speed for photos on wood, then tweak from there.

Common Mistakes to Avoid

• Using a JPEG from social media: Those are usually 72 DPI. Ask for the original file.
• Applying sharpening before resizing: If you resize after sharpening, it creates artifacts. Always resize first, then sharpen.
• Not accounting for material color: On dark materials, light engraving (burning) creates high contrast. On light materials, deep burning creates contrast. Prepping for one and using on the other will look terrible.

Bottom Line

Prepping a photo for laser engraving is 80% technical skill and 20% knowing what to avoid. The first time I did this right, the engraving looked like a photograph burned into wood. The client actually cried. That’s the kind of result you want, and it’s achievable if you follow these steps. If you’re using a Lumentum laser system, this process is tested and works—just don’t skip Step 5.