so i finally got my image to load. i am trying to engrave a photo on a canvas board, but getting significant banding.
speed 1000
power 99
convert to patterns
pattern density at 50
max margin optimization
lines per inch 225
1 pass
i didn’t spray paint it white first, its straight from the plastic. what should i be doing differently?
or should i not use canvas board and just use a canvas?
Hmm hard to say exactly, but it looks like that may be variability in the material? If this one is wrecked, I’d do a quick engrave by turning the canvas 45 degrees and trying a small sample.
If your light lines still run along the weave then you know it’s the material and not something weird with the machine/art.
@shogun, you got theories?
That’s odd. I have not seen that in canvas. Does it occur in any other material? It almost seems like a bump in the wheels.
Re-coat the canvas with gesso or flat white primer to reuse the canvas. As for the banding, try variable power and possibly tweaking the max and min power levels.
And expanding on @shogun, it does look like you may have residue buildup on the rails, wheels, belt (or any combination thereof).
Looking at that more closely, the banding seems to follow along thread lines on the canvas. It appears that every few threads there’s a thicker thread which may be of a different type of material? The weavers in the group could probably answer this better, but it really seems to me that it’s the material and not the laser.
Try engraving the same image on a piece of cardboard or something before you drive yourself crazy trying to find a problem with your Glowforge.
“Banding” has been brought up many times. You can eliminate it being a variance in the material by simply rotating it slightly and repeating a portion of the engrave. In most cases, it’ll still be there.
It appears to be an artifact of how the files are processed and sent back down to the machine for engraving. It’s particularly apparent on materials that are more “faithful” to small changes in power, like acrylic. It happens both vertically and, as in your case, horizontally.
You can play with different power and speed options to try and reduce it. I did a bunch of testing and posted the results (eflyguy account) a couple of years ago. It’s pretty irritating when you can’t just have a “solid” background engrave without all that “texture”…
In this one it’s clearly something with the material, you can see the fat threads.
I’d echo the rotate suggestion - see if you can get the bumpiness to work with your art instead of against it.
You’re right. This is what it looked like rotating it 90 degrees. On the other boards I have, I’ll try gesso first. Maybe it will fill in the gaps between the lines.
A thick (comparatively) layer of gesso can hide a multitude of sins!
