I have been and continue to experience an issue with the Laser not processing deep blacks correctly as they turn out almost white. This is not specific to either 1.6 or 10 watt modules as it occurs with both. Neither is it a Luban or Lightburn issue as it occurs with both brands of software. I am wondering if there is a Firmware problem. I am including some pictures as examples. Original photo, microscope pictures of the eye areas in both Luban and Lightburn as well as recent attempt with a photo.
Before you read: I never yet did images with the laser (only one very basic and quick test when the machine was new), so take everything I say below with a grain of salt.
Out of couriosty I loaded your image into Lightburn (standard settings, no tweaking) and looked at the preview:
From this, I’d infer that your engraving should be nicely black.
Doing the same in Luban and selecting dot engraving, and preview looks black enough to me also:
Same with line filled engraving:
So my take would be that it is not a software/rendering issue (assuming you did not misadjust some settings - how does your preview look like?), and as it affects both 1.6 and 10 W laser, my first shot would be that the controller has an issue. Perhaps PWM controll is somehow broken, or at high PWM duty cycles some power-switching part (FET?) breaks down… just guessing, but perhaps in the end a case for Snapmaker support.