Laser Engraving Fingerprints

[Javier Odom]

Engraving fingerprints is similar to engraving just about everything else. The most difficult part of engraving fingerprints is getting clean, usable fingerprints to engrave.

Engraving Fingerprints with the xTool F1 Ultra

1. Take fingerprint. (Key here is to not use a super high resolution image of the fingerprint, otherwise you may have to edit out textures of the paper. I like to use an actual fingerprint ink pad and a higher gloss paper (less texture). I have found scanning the image with a scanner tends to work better than with a camera, but a camera does the job. Your mileage may vary with the gloss paper. If you are going to do this as a business, I would suggest investing in a fingerprint scanner that scans straight to a digital format.)
2. Edit the fingerprint and save it as a single color (black) with a transparent background. (Gimp is free, and can handle this type of work easily.) If you want to get artsy with this, take it grayscale and engrave it with more character. Dealer's choice.
3. Open XCS, File, Import image..., get your png or whatever file you created.
4. The rest of this will depend on the object you are working with. This includes all aspects, be it flat, rounded, the material, et cetera. If you can engrave it, then it should be situation normal from here forward. If you are just starting, test out some of the presets on specific materials, and go from there.

Engraving a fingerprint, taken from Wikipedia (below), on the inside of a stainless steel watch back (had it handy from some testing), I tried Fiber IR, duration of 800µs (microseconds), power at 50%, dpi of 300, 2 passes, Atkinson bitmap mode, bi-directional engraving mode, and a frequency of 30 kHz. As it is an image, the only option XCS gives me is to engrave it, as opposed to etching or cutting. I like to use the Framing option to make sure the work area is correct. Close the case. Process, let it calculate an estimated time, Start (top right), press the xTool button on the screen. After the job ends (40 seconds), OK button.

Original Fingerprint Image:

Transparent Background Fingerprint Image (may still appear to have a white background in this forum/browser):

XCS screenshot (nothing fancy, just slapped the image on there for this post):

Engraved inside of watch back ("raw"):

Engraving inside of watch back (after super quick paper towel wipe):

I am curious if a third pass would be worthwhile or not. Also, if a spray would help define the engraving color better would be an interesting experiment.

If you try this and have any tweaks, questions, or recommendations on this process, feel free to reply.