I received my GF a few days ago and while everything is going quite well, I do have a few questions (some of which I already saw partly answered on the forum but for which I still have some doubts).
Why does the HD Graphic preset tend to favor “Convert to dots” instead of using “Varying power”? From what I understand, the first setting will basically either fire the laser at full power or not at all, how is that better than selecting a varying power for a more refined result?
Could you give me some examples on when to remove the masking on the materials I’ll use? I’ve tried with several variations with this and so far I’ve found that leaving it on is better to limit scorching mark when cutting, but it tends to limit the details on the final product when engraving.
On 1) your guess is as good as mine as to the companies logic. Use what works best for you, your art, and your material.
As to 2), you ask and then turned around and answered! With photoengraves you get better, sometimes much better detail with the mask removed. The downside is there is a lot more clean up. I always remove it for photos and always leave it on for filigrees and such where there is a lot of wood that won’t get lasered.
Vary power can just leave everything cut, and particularly with many Plywoods can be rather a mess while convert to dots can look a bit like a newspaper photo but not reveal messy variations in the plys.
For photos and drawings you want to use the Convert to Dots method. Vary Power is mainly used for 3D sculpting…creating gradients and bevelling an edge in the wood, carving the wood out more deeply in some places than others, etc.
Engraving is one color…what the dots method does is use spacing between the dots that it fires to simulate shades of gray. (Dithering.) From a distance, the eye processes the information as different shades.
3D engraving is going to leave everything uniformly charred, but deeper in some places than others. It physically sculpts down into the wood, but it’s going to appear very uniform until it’s scrubbed to remove the char. And it really only works well on hardwood or draft board, since plywood has a visible veneer.
Or if you apply dithering to your photos outside of the GF (like in Illustrator or something) because you prefer an alternative to the Floyd-Steinberg dithering algorithm GF uses you can use Vary Power to prevent the GF from dithering your dithered photo. Since it’s only going to see black or white you’ll get the same effect as convert to dots but you can change pattern types, dot types, etc.
I know it seems weird, but I tend to favor vary power for my regular photo prints as well. (Usually SD graphic vary setting.) I use vary power for probably 90% of all my printing. When I want to use dithering, I do it in my graphics program so I have control over and then burn it with vary power.
I think even the best results would look like a moth attack unless there was a lot of polyester (or nylon) in the canvas to melt the broken threads together. Otherwise, every broken thread would unravel eventually. What might work is to prepare the canvas as you would for painting with Gesso or modeling paste. As it is an acrylic it would be safe to laser and even if it broke a few threads they would still be bound and not unravel, However as @markevans36301 says experiments should be done on any material you have not lasered before, and anything thin like cardboard or fabric etc should start testing at the lowest power highest speed first and work till you get something reasonable, watching it like a hawk the whole time.