Hello! I am wondering what king of setting do i have to make to engrave a photo with a cnc 3018 GRBL controller and 5.5 mw diode laser. For example : use grayscale, threshold, jarvis, grayscale with pass-through with air assist and dpi set to 300, b-directional moves, overscannig or not, the power and speed for 3mm light color plywood …
If somebody can help me i would appreciate so much. Thanks
I’m not that familiar with diode lasers, but I’ve seen plenty done with them. You’ll want to use Jarvis or Stucki more than likely. You can probably go higher than 300dpi, but it’s probably best to stick with whatever the image is, I think. But that’s a good place to experiment. I’d probably set overscanning, but with a diode you’re moving a lot slower than I am on a 100w co2. I’m not sure of power, maybe someone else can help out in that area.
Are you doing any pre-processing of the image before you import to Lightburn?
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Yes. I am doing pre-processing in corel or photoshop. I only mess with brightnes/contrasts/shadows/darks. I saw some tutorials on yt and i saw that i have to make a picture brighter to have a good result.
that is my first try with grayscale and it s looking awful… thank you so much, i will try what you said.
Yeah, grayscale is a different beast altogether.
Thank you! Hope it will work 
No problem. Let us know how it turns out.
Grayscale with diode lasers is much easier than with CO2. If that was your first grayscale result, you might have a settings issue. Starting with a color or black and white photo, you should be able to do things like this:
That image was done with a 4.5w diode laser, using no external image processing - I just dropped the image into LightBurn, entered the settings, made some adjustments to contrast and brightness, and burned it.
Full settings are shown with the original post here:
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How long did that take to make?
I buyed my license last night…so i guess this will come in the next update so i will have to renew my license…that’s not quite nice…
No, that post was back in June. These features were released a while ago, and even if they were released next month, your license includes all updates for a year after your purchase date. Incorrect accusations are not nice either. 
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I believe the burn time was about 40 mins.
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sorry for that but it was no
sorry for that… but it was not an accusation it was a guess 
it is working fast on grayscale but i still have a problem…
if the photo its darker it engraves quite ok ( a little bit overburned but it’s because of max power i guess) but if i adjust contrast/brightness and gamma to enlight the photo it wont engrave at all…
Low contrast and brightness with 1 gamma
High contrast and brightness with 0.8 gamma
both with 300 dpi same speed&power
Any suggestions?
I think you have an issue with your settings. In the console, type $$ and press enter. Copy the text that it outputs and paste it here. Then click, Edit > Device Settings, and tell me what value you have for “S Value Max” in the settings box.
Here is a good article to help you with your photo printing
https://www.instructables.com/id/Optimize-Your-Art-for-Laser-Engraving/
Bun Noroc din Vancouver , Washington USA
( i saw on YT tut)
$31 should be 0, not 1. (in the console, type $31=0 and press enter)
Your settings for maximum speed for the X and Y axis are both 1000 mm/minute, which is very slow (16.66 mm/sec). If you try to use any speed faster than that, the controller will limit the speed, and lower the power to compensate for it, and that will greatly reduce your power output resolution.
Try using $110=6000 and $111=6000
This looks like a machine that is configured for CNC use, not for laser use, as all of the speed and acceleration settings are very low. Acceleration is $120 and $121 = you might want to increase those as well. Try doubling them, and if your motors do not lose steps when running a few jobs, try doubling them again.