Note, this is from an email sent to Lightburn, now open to forum for answers.
Hello,
I have been using your product for over a year now, and up to this point, everything has been fine. Recently, I have had an issue with the grayscale function not working properly with my images. Worst off, it worked fine with them only days ago, yet when I reopened them in file, the preview shows that they are not being scanned (red lines). The image can be lasered with all other functions ie. Stucki, Dither, Halftone, etc., but with Grayscale selected, the image is not scanned correctly and is not laserable. I have a Lightburn license, and am using version 1.3.01. I have tried both PNG, and SVG imported images, and even a JPEG. All fail with grayscale now. The uploaded pics show the same image with both Grayscale and Stucki. As you can see, the grayscale shows no red pass lines, while the stucki does. The end result is that the laser does not make an image for grayscale, and instead just burns the wood or material with nothing to show. Can you offer a solution or help please? Thank you.
Looks to me like you have multiple images loaded and using “Cut Selected Graphics” enabled in Laser window. Have you tried selecting both sets of graphics before previewing?
Yes. The large flower image is actually three flowers all together in one image. There is another image of a branch along with the three flowers, and they are two images. Remember, the image with the branch added has Stucki selected, and it along with the flower set works fine as it has red scan lines across it. I could have 20 separate images on the cutting zone, as long as I select them all, then “cut selected shapes” will apply no matter what. Grayscale still wont activate. At least it will not “now”. My grayscale worked several times before.
Hi,
Well, there seems to be a kink in the software. I’ll explain: the sakura flowers are just an example I am using instead of my actual project which I have completed before only a few days ago using the settings 50,20,20 (50 spd, 20 max, 20 min). Yes, you can force LB to accept similar min maxes for grayscale. But when I tried the same project again, after seeing the traversal lines gone, it no longer worked. I changed nothing because I worked hard to get everything right, so thats how I saved the project. I just tried the sakuras with both 50,30,10 and 50,20,20 , and now it works (still no red traversal lines), but when I go back to my original project, grayscale fails. This is why I said problems only occurred recently. LB hasnt been kind to a few of my projects lately. I have included a sample image of one of my projects that I completed using this image (dragon scales), but now doesnt work. It no longer shows traversal lines, and simply burns an empty hole in my base material. sakura and branch.lbrn2 (1.6 MB)
Ok, first off, correction on my previous message. The sakuras are not working. While they are creating the general shapes, the output is full max (hard to explain, just think craters). Now, back to what your picture shows. The image you show has red on the borders of the image and dont “fill” the images. The sakura you show in the preview is gray, not pink (when red traversal lines cross it). The branch is gray/black , not pink. The scales are gray/black, not pink. If you look at the original first images that I sent at start of forum, you will see the Stucki version shows this “pink” shading across the images. This is absolutely necessary for the image to come out correctly on the material. These are the image traversal lines needed which are not in your sample pic. Yours only shows red around the borders which shows there is a problem. This is grayscale not working.
I think you may not be fundamentally understanding how grayscale works in this case. You see traversal moves within dots of Stucki because that’s a dithered model. All on or all off so shading is approximated through gaps in burns. This is why you would see traversal moves in between those dots.
Grayscale will always be on where a color is present, just at varying power which is why you see different shades of gray as long as “Shade according to power” is on. And also no traversal moves.
Again, is there a reason you’re trying to use grayscale? And is there a reason you were trying to use a single value for both min and max? I suspect there’s something fundamental you’re attempting that I’m not able to understand.
To prove, I am showing the project when it was successful a few days ago. I struggled to get the image to finally “go pink”, and after some adjusting of the settings and even creating a cut border, it finally showed up properly in the preview window. Once this was achieved, the image engraved properly on the wood. Only after it went pink in the preview did it work on the engrave.
I use a 50,20,20 so as to not cut too deeply into the wood. I use a low and slow method for some projects because I want the quality to be better. If I use a 50,30,10 for the scales, the wood burns too much. Likewise, if I use a higher speed, the quality suffers. The point is to be able to “feel” the scales, not just see them… they actually have a scale like texture.
This looks like it was actually done with a dithered mode. You can see discrete dots where shading is approximated.
I don’t think this is doing what you think it’s doing.
This basically says, use a single power for the entirety of the image irrespective of grayscale level. So no matter what the picture you would just get the same burn throughout. I think this is demonstrated in what you’re seeing.
This does sound like something for grayscale as you should be able to get variable depth. Note that you won’t necessarily get variable shading on most CO2 setups.
Read through this topic on how grayscale functions. Note that this was under the context of diode lasers where variable shading can genuinely be achieved but the principle for how power is determined is the same.
I am showing images of the burns I just made using 50,20,10 (even LOWER than what I normally use, and respective of what you would suggest for grayscale), and I get either pure burn, or the image engrave with a heavier burn. How is it good one day and bad the next?
Note that I made no specific recommendations for settings.
I suspect you’re not comparing apples to apples in the tests.
In this particular example it seems to me you’re just going way too slow for the power of your laser.
Did you read through the previous Topic? I have a couple of posts there that are very instructive in understanding the impact of grayscale values and the min-max settings.
Berainlb,
When I say “respective” I mean that you are saying the grayscale should have varying min/max powers. I changed the values to “respect” that. I just lowered the dpi (it was strangely 491), and the gamma from 1.0 (once again, not my intended value) to .450 where it should be, which lightened the image which should lower the power output and still got craters.
In any case you can see that there is variable power based on the texture that’s visible.
So a few things possibly going on:
you may not have enough variability in grayscale from lightest to darkest in the source image. If you review the linked Topic I have a post that illustrates how the entire grayscale gradient gets mapped to min and max power. If you do not use the full 256 range of values you’ll be working in a reduced band of power variation.
What is the lowest power that your laser will fire? I’d suggest setting that to your min %
You want max power to be the highest value that you’d want being used for absolute black
Once min and max are set adjust speed to get the level of burn that you want overall.
right!, So 50, 30, 10 ! Im not saying that to mock you, Im saying these values because they align with what you just suggested. 10 is my min power (8 is the absolute lowest, but my laser wont spit out anything there) 30 is my max, because if I go any higher, it will burn through the 1/8" balsa wood Im using, and 50 is the most appropriate speed to allow these laser power values time enough to settle in the material. I wasnt playing when I said I spent time making these values. Once I saw them work perfectly on some of my other projects, I use it all the time for similar materials. 50,30, 10 for 1/8" balsa/birch wood. Period! Now we’re kinda getting off track talking laser values when the real reason I posted, is because NOTHING is engraving now for grayscale.
