Very grainy (I’m guessing some dpi or dithering adjustments might help that)
And since the background is white it shouldn’t have touched it. My result should be a negative of the original image. Which it almost is… ultimate goal right now is black on white canvas to make ablack and white image. Can i fix this?
If you have a binary medium, grayscale is not the algorithm to use. You need to use dithering to get different levels of gray.
Though, it appears that you only want to get the power required to burn the black layer and reveal the white one. So, just do a normal material test and check out at which power level the top layer is removed completely.
I haven’t played with images yet, but if I understand the theory correctly, your min power should be set so that it doesn’t mark (just BARELY) and your max power should be set to produce the darkest color possible. The speed should be set such that both of these are possible at the same speed.
Looks to me like both your min and max power are too high for the set speed.
Again, no experience. Still researching. I’ve got some image work to do in a month or so…
As misken said, this will be difficult on the medium you’ve chosen. Thickness of the paint will drastically affect results. Better to use a dither (halftone, jarvis, stucki, etc) so you don’t need quite as tight control over power/speed and coating thickness.
Unless the “background” is actually needed, you should probably mask it just to reduce chance for error and speed up the job.
Out of curiosity…I see your test grid is set to mm/s @ 100-300 (6000-18,000 mm/min) That’s pretty fast for a diode laser. Are you sure your machine can actually achieve those speeds? I’ve not yet found anything I could mark very well at speeds over about 10,000mm/min with my 20W, but I’ve also never tried burning paint other than coated aluminum business card.
And though it is compressed and still needs some settings tweeks I can see the light
Idk if max or min power needs bumped to see the fine details or if those will just show up better when it reaches its full 12"x9" size, but it’s close.
I would imagine the texture of the canvas would cause a lot of grief as the paint would tend to sag/pool into the low spots of the weave and require more power to reveal the white. Hence, the grainy/blotchy result. I suspect. Maybe try it on smooth glass, tile, or hardboard as a proof of concept. Alternatively, several VERY thin coats of black or a smooth sanded base of white. Tho, I know that last one kinda defeats the purpose of canvas.
I find the added texture adds to the aesthetic. And as i do it more I get more practice spraying the paint in thin consistent layers removing some of the variation. I’ve also seen some people use a brushed on base coat of white that they sand down to fill the pores as a flat base coat before adding any color or black top coat. I’ll see how this turns out and perhaps move to a base coat in the future.
I did also forget to focus the laser before I burned the test swatch I suppose that will probably affect those fine details,too.
The purpose of burning the circle was merely to test whether the setting I found would produce the full spectrum of greys I expected. It did not and now i know why.
The setting within the controller limit this, in and effort to protect the machine from humans trying hard to damage it.
These limit settings are within controllers firmware control. They are generally based on the physics that indicate what the machine can accomplish, within it’s engineered limits… They are, also, usually very conservative.
If I gave you my file that include 1600mm/s speeds, what would your machine do? … that’s just one of the reasons for speed limits with the controller.
After watching the videos you posted im left to wonder whether I can calculate my max dpi if i know the diameter of my laser point without arduous repeat testing…
In reality, the interval is usually whatever damage it does to the material. There is no real edge to most laser beams and ss lasers are usually rectangular.
If the material is damaged at less power it will change the interval as most materials will.
Do it like the video spells it out and visually look at the results to see the damage… That will get you the best interval.
