Those last 2 pictures look good at a distance Peter, but what's with all the dots when you make them bigger? My first couple of tries converting to black and white in Corel, the engravings came out like those did. It was because I had the intensity set to high when I used Jarvis to convert. I'm assuming your converting them if your just pulsing your laser on and off. Try cutting back on the intensity and allot of those dots will disappear and you will find a happy medium with the image. That's probably why using halftone did not give me any good results either. In CorelPaint the halftone conversion does not let you adjust the intensity. I have been trying to make my engravings look good at a distance and up close.
Also give us some details on your settings concerning the feedrates your running, tool your calling out, stepover, ect and the size of the beam you were able to focus laser down to. Also what software and process are you using to convert your image?
It just seems like would be allot easier to add an external laser control circuit and it may be because I'm running a servo system instead of steppers. I have the same size motor on the Z axis as I do on the X & Y which accelerates very fast without stalling. It's a very responsive setup when turning the laser on and off. Also I do not need any special PP and the only thing I changed in the Mach profile is set the CV mode to Plasma. Everything else is set just like rotary engraving. It did not start out that way but progressed into a simpler setup.
I watched your video and I use my laser beam to find the edge by placing a piece of black anodized aluminum against my wood in the corner, zero then MDI to the center of my stock and zero again. The laser beam makes a perfect edge finder. Also how the heck can you stand not to be able to see the progress of your project with that big shoe on there? I know it would drive me crazy not to be able see the wood being fried.
Even when I was making Litho's, I made the smallest shoe possible and as far as I was concerned, it was still to big. I'm so happy now that I don't even need a shoe to laser engrave.
Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver