I have a K40, Mini-Grbl board, Lightburn software. It’s a hobby laser (meaning I get back to it every month or so). I understand the physics (DPI, line interval, ramp test, alignment spot on in all 4 corners, mirrors/lens cleaned, etc.) and I have sometimes successfully burned my own photos to birch plywood but I rarely seem to be able to repeat the process with the NEXT photo even with the same settings. Some photos come out awesome, the next photo not so much. Do I need to take a course in photo processing to understand Gamma, Contrast, Brightness and the effect on individual photos? Most videos that I see indicate ‘processing’ the photo first before trying to burn.
An indication of what I am trying to burn on birch ply but failing>. Perhaps this just isn’t possible.

How are you preparing your images? Lightburn, Imag r?

I’ve tried both. Imagr has provided ME with the best results so far however the image does not have much definition. The burn isn’t bad, just too dark?? I guess i’m looking for advice on the ‘prepare picture’ part but not exactly sure.
Imagr processed- BMP

Yeah, mine do that too, but I also worked with canvas that has no grain. I finally learned to make multiple starts on the material, burning the first inch or two. Then I make adjustments, move the start point, and do it again.

Maybe this link can help. I also included the Part-2 video.

Are you using the pass through option on the layer when you pre-process the artwork?

Figured someone would put a link to Laser Everything video. It covers what most people are clueless about and that is the proper interval for machine and material. A must watch for anyone… along with an excellent description on using dot-width adjust ability on a layer.

It might help to think of the laser more like a printing press, it only does burnt and not burnt… Not exactly true, but the material you use has a usable range for a gray scale, which is very compressed when compared to a photograph with an infinite range in gray scale. On a co2, grayscale option if for 3d type applications.

Even a bmp is limited to 255 shades/steps between burn and not burn… 256 steps is probably exceeding what most materials are capable of… You can probably see that the new 32bit machines using 16bit pwm generation isn’t really buying you anything when it comes to range… so you have 65,536 steps… ?

You can still do some pretty incredible images, although not what I call a photograph.

A good dither is probably the best approach.

@Bulldog does some pretty incredible work… These are done on a fiber, but it’s an example of what can be done… Although a smaller spot, increased resolution, doesn’t change what I’ve said about a gray range.

Good luck


thanks for the links and advice… Had a chance to watch the vids to re-group and test DPI, DWA, etc using gradient scale. My sweet spot on the K40 seems to be around 100dpi so I imported the same pic to Lightburn, resized to 100DPI, 100S, 15 Power, Greyscale and results were a black square (left on pic). LOL. So, i imported the pic into Imag-r, resized, set DPI and used CO2 Nero Greyscale and passthrough mode in Lightburn (sample on Right in pic).
Obviously the results of focusing on DPI, DWA and such is not working for me so far. LOL

What is the best manner in which to resize a photo? The sample one of the house was taken with my drone and info on the photo indicates 72DPI and 3000x2250 pixels which I believe is about 44 inches wide. I only need 8-10" wide… Suggestions welcome on best manner in which to resize and get this into Lightburn so I can apply my proper DPI/DWA/Speed/Power settings and test?