Wow! Tell your wife that’s a beautiful drawing, and oh yeah, nice job with the laser rpegg. 
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Beautiful artwork @rpegg ….(tell your wife). 
And great job on the Engrave! 
(If it’s not too much trouble, would you mind starting a new Topic for your projects instead of putting them in the same thread? )
It’s going to make it easier for me to not miss them while putting together the Weekly Highlights, and easier for other people to see them who are only popping in occasionally to see the goodies in the category. 
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When I have something useful to show it will go in a new thread. Right now just testing a gazilliion things. Not even projects, just settings and fit tests most of which has been done better by someone else.
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Chuckle! I’m going to link it anyway, so it gets shown off either way. (You starting a new topic just makes it a little easier on me.)
You’re famous now…got to come out of that shell a little. 
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Infamous maybe. Tuesday night for a concert, a rag tag bunch of us played for about 500 folks. We jam together regularly but don’t ever practice as a group. I didn’t know they were going to go low on this song. Normally I play banjo but was playing the upright bass here.
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LOVE it! Gettin’ down with that bass!
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Being a complete novice here… Is the answer here the greyscale curve or power or speed or a combination? And I guess the biggest question for me is, how would a novice like me be able to tell in order to adjust the right thing(s)?
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What Philip is saying is that the answer is in how you prepare the file first.
There are things you can do to increase the contrast between the dark and light areas, that will make the grayscale treatment by the GFUI come out the way you want it to be. Making some parts a little lighter or darker than they appear in the original scan will dramatically improve the results.
You would do that in something like Photoshop or GIMP. It’s a simple process with a couple of steps.
(I think we’ve got it in the tutorials, but if not, it’s easy enough to add.)
You really only have two colors to work with in lasering - burned and not burned. The different shades have to do with how thickly the burned parts are laid down on the material…more spacing between the burn lines makes it “appear” lighter from a distance. Tightly spaced burned lines “appear” darker.
What the GF software does is take the grayscale image that you give it and interpret it as different lines per inch (spacing) to try to approximate the effect you want to achieve. But the more contrast between areas of similar gray value that you have, the easier that becomes for the laser to achieve.
(Did that help, or did it just muddy the waters further? That’s the reason we’re trying to put some simple tutorials together…the steps are simple, but unless they’ve been doing it for a while, most folks aren’t aware of them.)
Bottom line:
You’ll get good results just by scanning the image in the GFUI and printing it. You’ll get better results if you do a little prep work to the file first.
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Thanks. I’m a long time Photoshop user, so I get how the curves work. But I don’t get lasers yet. So is it always a matter of curve and never a matter of power/speed? I see your point about “2 shades.” In that case would I be better off converting a bitmap to a 2 colored dithered image myself so I have complete control over the result?
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So you scanned that sketch in the bed and printed it?
Thanks for the demo!
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You have the most control over it that way, (and I prefer to have control over how it turns out), so yeah, that’s what I do. If you use Photoshop, you’re golden.
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Great info! Thanks!
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No I uploaded it from my files.
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I see below that you scanned this without the Glowforge. My understanding is that with using the Glowforge’s camera you can use keys on the keyboard to adjust levels (or maybe just contrast or something). Can you do the same thing with an image that you’ve brought in the way you did?
If that isn’t possible…
(That’s Dennis)
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Sure but it’s not as simple as darkening or lightening the lines. For that image I would need to play with shadows and highlights. Some areas I would need to darken or lighten separately from others. I have the correct S/W to do it, just not the desire until I’m ready to move from understanding to creation mode.
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At this point I’m unsure of how Glowforge’s software changes a scan, but it may be more complicated than darken/lighten. Maybe not, or maybe in-the-future thanks to cloud magic.
Either way, what a great drawing!
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Yes! Wonderful detail.
The faint background branches really give the image depth.
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My answer is going to be quite a bit different than Jules. I run a plain gradient engrave on everything first, no adjustments. I pick a speed based on similarity to other materials I’ve tested.
Once you do that you will see a lot of variance in coloring depending on material. Some materials shade more evenly and produce a greater range of tonality than others. The coloring doesn’t just come from it being burnt or not. The longer you linger on one spot with the laser, and the higher the power, the more sap and vaporized material will come out darkening that area and surrounding. You actually want to avoid burning if you can. If soot rubs off, you might have gone too far. Some woods give a very nice range of coloring if you get your speed and power right, without being burnt.
As far as what to adjust in the laser if your first gradient doesn’t come out, I always try to go as fast as possible. This will require more power, but takes less time. So if your engrave is too dark, speed it up. If you’re at max speed, turn the power down. If you’re at max speed and lowest power, adjust the grayscale to make the darkest color lighter. I always do that one last.
If it’s STILL too dark, you could always put a thin layer, like an additional masking layer on top to soak up some of the power. You’ll lose some of the fine details on the light end, but might allow you to engrave very sensitive woods like cedar without the charring. I’ve had to do this.
The photoshop curves topic is something to work with after you’ve gotten your best tonal range dialed in from power/speed. If you see one range lacking, just adjust and try again. Save the preset with the wood name, speed, and power settings. Then any time you know you’re using that material, you’ll have all your info and an easily applicable preset ready to go.
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Indeed quite a different response. Seems I’m going to have quite a bit of experimentation to do. 
Thanks so much for that insight!
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It’s great to finally have the opportunity to see how actual GF users with different backgrounds approach their laser jobs, especially for those of us new to lasing…
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