Gosh… The basketweave pattern! Seems like forever ago! I’ll have to revisit that.
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Are the jaggies actually visible (with a microscope)? With the spot being ten times bigger and having and indistinct edge due to the Gaussian distribution I will be surprised if they are.
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From everything I have read here, I still think that the reason the hearts are “engraved” so deeply is that they were using the “cut” settings. You mentioned the wood was thicker than the laser can cut. So that depth is the cut depth based on the material you told it was in the machine.
SVGs, as I understand it, group all of the vectors of a particular color into a set. So if you had red, green, and black vectors, you’d have three sets.
Each set is assigned an operation: cut, score, engrave. And each can be assigned specific settings for power, speed, etc.
By default, black vectors are assigned “cut”.
(Again, I don’t have a laser, but that’s what I’ve picked up from the forum. And that’s why the black of the dress did not equal the depth as the black SVG.
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If it was a cut operation wouldn’t it have just cut along the outline, not carved out a pocket.
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Thanks. But I’ve been pretty clear the entire time that they were all set the exact same way. Besides, you can’t set anything with a fill to cut.
I haven’t found that to be the case. In fact, it always seems to be correct when it picks the operation for things. I’m guessing that’s based on being filled or not.
I think Dan’s recent suggestion is probably going to be the answer. I just got tied up working on another project last night. Maybe tonight I’ll get the chance. I’ll post the result here, of course.
Indeed.
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Tom, there’s a big difference between engrave on an svg and a raster. They had to change the power curve for raster to come out looking good.
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Correct. Fills are assumed to be engraves and lines are assumed to be cuts. Colors just separate the objects so you can re-order them in the GFUI or change the operation (when allowed - like cut to score).
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Right. I’m seeing that very clearly now. 
Which is why trying to reproduce depth as seen in the Glowforge medallion is making no sense to me.
But as soon as I possibly can (tonight, please, Wife and kids?), I’ll try Dan’s suggestion. I understand what he was saying and I think it’ll do the trick. And I understand the limitations of what he described, so I’m not expecting perfection. I’ll happily post my results and interpretation of them as soon as I have them.
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So does it just ignore the fill if you tell it to cut or score a filled vector shape?
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Ah. Thanks for the correction.
It’s not that you need to increase contrast, it’s that you are likely to prefer the output if you do. But its pretty subjective and you certainly lose detail that someone else may want. I can see options in the tools to boost it but it would be challenging to do automagically.
At lower resolutions, yes. Higher resolutions, no. What resolution they appear at depends on the material.
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Yes. The operation choice is convert to cut or convert to score. It defaults to engrave.
Wow… I got getting a .3" engrave at 100/84/340. That’s insane! (And probably pretty useless as an engrave setting.) It was marvelous to watch though. But I canceled the job after a few minutes. Wasn’t very safe and wasn’t at all worth letting it finish. But it was a GREAT little test.
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A wonder if the end result can be simulated / previewed by resampling the image at the specified LPI and the DPI resulting from tube bandwidth / speed and then applying a Gaussian blur with the beam parameters.
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First off, that looks pretty great! I particularly like the hearts – nice job on that!
Wood etching 101:
First you don’t have 256 colors in wood. You have natural (use light wood in most cases) all the way to a dark brown. And most of the dark greys to black map to the dark brown. Net, you have about 10 levels from lightest to darkest (maybe only 8 or maybe you’re really good and can get 16).
Second, as I say, there are more lighter colors than darker colors so if the image is a dark one you’ll have trouble getting 10 levels out of it.
Third, images tend to have big areas of white with a lot of subtle definition so that’s almost always going to be an area of focus. For example, your image has faces and these are almost always the lightest, the most important, and the most difficult parts of an image.
Putting this all together, here is a process to follow (I’ve spent 100s of hours wandering around trying things but this process seems to work better than all my other efforts).
- Most images are too dark so lighten the image a little (your mileage will vary: you’ll get a feel for it pretty quickly).
- You’ll probably need more contrast so up that a few points. This will add definition you can use to the light areas but hurt the dark areas – don’t try to fix that, the dark areas were lost to you anyway.
- Look for really light areas that will “wash out.” Select those and up the contrast a little more.
- I generally put more power than is recommended but that generally results in a deeper etch in the black areas, not a darker etch. I think you got it right in this one (the blacks are very black).
That’s it. You don’t need to gray scale it, you don’t need to dither it, or process it much at all. I spent 100s of hours trying to do the processing but the laser software will apply it’s own algorithm so the best you can hope for is to hand it something it can work with. You just don’t have control over this.
If you want to get a sense of what it will look like try this: go to grayscale, go to a 10 color palette and make it sepia.
This is actually pretty easy. I tend to try to over control it which is why it’s taken me so long to figure out…
Dave Menconi
Former Techshop Member 
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