NOTE: This is obsolete, newer Lightburn versions produce good image engraving without extra processing.
this is a rough draft brain dump, feel free to add to it, including adding more software methods. I’ll clean it up later
Paint.net method
https://forums.getpaint.net/topic/18811-ed-harvey-effects-v-40-2012-02-13
crop first, then resize to desired print size. 400 DPI recommended.
Adjustments, levels, move the center Output slider up to wash out the color, .33 worked for mine
Effects, Unsharp Mask: 30, 20, 6
Effects, Photo, Sharpen, max it
Effects, Stylize, Halftone: line, angle 0, adjust rest for effect
save as jpg, high quality
import to lightburn
set BMP Engrave to speed 1000, power 20% (big laser), mode X_swing
add your shapes for cutting border
run in 2 sessions, engrave first, then cut later.
set focus about 2mm higher than you normally would, run the engrave only.
set focus normal, taking care not to move the workpiece, run the cuts only.