Thank you! You answered my question precisely. Going to copy/paste it for reference. 
1 Like
…but, do you have to remove the background of say, a jpeg before you can save it as a png? Just because you save something as a png doesn’t necessarily mean that it then has no background…like if you took a jpeg and re-saved it as a png? Clear as mud?
1 Like
Jpegs don’t have the ability to do a transparent background - there’s a different level of data captured in png files, and as Chris pointed out, a different method of compression.
If you save a file that has a transparent background as a jpeg, a white background will be assigned to it.
But on the other hand, you can have a png file that has an opaque background as well. (They are both just different formats/methods for saving the data in the file. But jpeg does not allow for transparency. Png does.)
There is no hard and fast rule for using one over the other as far as this process goes. Png file sizes can be much larger, and they tend to give sharper edges if you are looking for them…but you might have to resize them.
You can Google “Png vs Jpeg” for more information if you want the technical details.
4 Likes
PNG files can have a transparent background, but they don’t have to. If you save a JPG as a PNG without doing anything to it, you would not have a transparent background. If you delete the background of your JPG in a photo editing program (like photoshop or Affinity photo) and then save it as a PNG, and select “maintain transparency” or click the “transparency” checkbox in the save dialog, then your PNG will have a transparent “Alpha” channel.
Heres some more info lifted from a website:
PNG files (Portable Network Graphic) were invented to replace the GIF format (Graphics Interchange Format) that was quite popular at the time for images on the internet. They really weren’t intended to be used for professional-quality photos. Currently on the internet, you will primarily see JPEG and PNG files followed by the lingering GIFS.
PNG files:
can only be saved compressed (“lossless” – reduces file size)
can hold an alpha channel (transparency)
TIFF files (Tagged Image File Format) on the other hand:
can be opened with almost every image program (it’s an extremely common format)
can be saved compressed or uncompressed
can store “layers” within (great for use with Adobe’s high-end Photoshop for example)
can hold all color, color depths and color groups (like RGB and CMYK)
can save 16-bits per channel scans (your 48-bit scanner setting)
can store IPTC metadata (captions etc.)
JPEG/JPG (Joint Photographic Experts Group) also uses compression. And it’s even more severe because it’s a form of lossy compression. Lossy means your file size will typically be even smaller than that of lossless, but at the cost of reduced image quality. And once the detail is gone – it’s gone. If you’re lucky, your eye won’t be able to see what’s now missing.
Even worse, every time you re-save a JPEG as a JPEG, you are “tossing out” even more information in addition to the information you got rid of before. It’s compounding detail loss!
5 Likes
Jules and jbv…thank you both very much. I will read up on it.
1 Like
Okay, I promise to get back to work on another practical project but before this plays out I found out that pencil drawing translates into laser engraves extremely well.
22 Likes
Nice. The bottom one is the wild one.
I definitely love the high contrast pencil drawing one!
I’m trying to upload image in Illustrator and change to grayscale, i’ve also tried embedding and linking and googling for suggestions, but I keep ending up with a blue question mark and no images. Can you tell me your steps? Only way I have had success is when I trace the image, which leaves a very black and white result (which I like), similar to what happens if I use the app to upload.
I would love to print out a photo like this but I just can’t figure it out!
Also, along those lines if you or anyone knows…is there a way to use the app to upload and not have it crop to a square?
THANKS for any help!!!
I’m not an Adobe customer but I think among their products, photoshop would be your go to.
If you are not familiar, there is a training matrix here in the forums under “glowforge tips and tricks” I’m 99% sure the work flow is covered there for Adobe people.
3 Likes
- Load your photo into a new Illustrator document sized with a 20" x 12" artboard.
(If you want to clean it up first you would need to do that in another program, but lets assume it’s a great photo with great contrast.)
Just drag the photo over from your desktop and drop it on the open Illustrator file.
-
Select the picture by clicking on it, then click on the Embed icon in the top row.
-
Drag out a rectangle around it to use as a cutting line. (No Fill Color, but give it a Stroke color.)
(The rectangle will be a vector line, and it will be interpreted as a Cut line.) -
Now you save the file as an SVG. When you do you need to click the Embed Image radio dial as explained in this tutorial:
- Final step…open the Glowforge app to the Dashboard, drag the SVG file over anywhere onto the Dashboard and let it go. The file will open up in the Glowforge interface ready to go, with a Photo engrave set up already, and a cutline around the image. Load your material and send it to print. The Glowforge interface will turn the photo into grayscale for you, using dithering in the Photo Engrave settings.
If you want to get fancier with it, instead of dragging out a rectangle for cutting, drag out an oval and place it over the photo wherever you want it. Then just save the SVG. The possibilities are endless, but starting simple is a good bet at first. The rest will come before you know it.
2 Likes
Thanks so much @Jules. My eyes and brain jumped over that 2nd part where you select Embed when you are saving the .svg. That worked!!! Greatly appreciated. It’s a really cool effect compared to the other engravings I’ve been doing directly from the app, which I love! They have a huge contrast, silk screen or stamp kind of look.
Now I just need to figure out why the “cut” command isn’t consistently working. Sometimes it does and well, like on this one, I’ll try again in the morning. That will be the 4th time on this…still hasn’t cut through. I’ve adjusted the depth. The material is 0.125 and I even tried setting to 0.25, still didn’t cut through. This has happened with both proofgrade and non proofgrade.
That’s actually the opposite of what you’re trying to achieve. You’re not telling it how thick something is so it can adjust itself to “cut more”. You’re simply telling it where the top of the material is and thus where to focus. By telling it the material is thicker than it is, you’re moving the focus up above the material and reducing the concentrated power delivered to the material itself. You get a wider beam hitting the material which is less power for a given area on the material. That’s not a bad way to make score lines thicker because you want a thicker line without having to do an engrave but it will hinder your attempts to cut.
With thick material you sometimes might want to tell it the material is thinner than it is so you move the focus of the laser beam & thus the power into the material. That can help cut thicker stuff because the lower powered defocused portion of the beam (think of it like it’s an hourglass with the most power right at the waist - the focus point) is evenly split between the top half of the material and the bottom half.
However, you shouldn’t need to do that with 1/8" thick material. It should cut through on a single pass. Check your power & speed settings (slow it down ifit doesn’t cut at the speed you’re using and you’re at Full Power). Or set it to do another pass.
Also check it’s clean - that’s the mirror on the left under the side top, the mirror in the head under the magnetic top and the lens itself. Also make sure the lens is in the right side up (bump up).
4 Likes
Thanks so much for the thorough explanation that the measurement is where it hits top of material. That helps a ton.
I did clean mirror…I’ll check out the lens again. Would it even cut at all if it wasn’t right side up? Because I have had successful cuts. The thing is, it’s been totally hit or miss.
Sometimes the cut doesn’t go through on proofgrade, so I’m not even adjusting the settings. I could understand failed operation if it’s me doing my hack job opposite settings, (which sometimes did work!), but with proofgrade, I was more taken aback.
So you recommend full power, slower speed, set to something like 0.08, and possibly two passes, right?
Okay, done! Thanks again for taking the time to help me out on this! Greatly appreciated!
Is there any reference guide that shows/tells different things you achieve by adjusting power/speed? I couldn’t find anything in community.
Nothing specifically, but here and there you’ll find something like the following:
The faster the speed the less energy delivered to any given spot in the material. The higher the power setting the more energy delivered to any given spot in the material. To deliver the least amount of energy, max out the speed and minimize the power. For safety reasons the GFUI defaults to a speed of 500 and power of 1 for cuts when proofgrade is not used. To deliver the greatest amount of energy minimize speed and maximize power. For cuts this would be Full power and a speed of 100.
In general you want to use the fastest speed and least amount of power that gets the job done. But this is in general. For a given material, you may want to go slow with less power and use multiple passes. The main reason you may want to go slower is how it leaves the edge of your material. Nothing firm here other than if you don’t like it, try adjusting speed and power to see what happens.
Power settings from 1 to 100 are identical between the Pro, Basic and Plus machines. Full power delivers more energy on the Pro than it does on the Basic. I don’t recall if the Plus gets the 40W or 45W tube.
The settings are not necessarily linear. I forget which one is not, but someone may be by to point it out.
1 Like
Neither from what I recall.
Back when they went from ipm and % power they published a spreadsheet so those of us with machines (it was back in the days of Pre-Release Units) could translate our settings from old to new (& kvetch about non-meaningful and non-linear units). I don’t know that it still relates as they’ve done tweaks to both power & speed settings so I’m hesitant to link to it.
While there were a couple of testing template designs before the switch, there were lots uploaded afterwards. Testing is the only sure way to nail these down.
That can happen if the PG material isn’t flat. Using pins or magnets helps. If you out it on the bed and tap it with your fingers you’ll hear if it’s solid against the bed (thunk) or raised a bit (hollow echo). If it’s bowed up off the bed in the center that means the edges are likely flat - flip it over and the edges will be raised and the center will be flat against the bed. Then it’s easy to pin down the edges (hard to flatten the middle of a sheet).
Also if you’re using PG that’s already had something cut out of it, when it scans for the height it may hit the bed instead of the material. Use the Set Focus to make sure it grabs the height from material you’re planning to cut.
@caribis2 & @jamesdhatch This is SO HELPFUL. I did just print out the pin file, so I’ve got those ready to go. I hadn’t thought of that, and I do have some super strong magnets I can throw in there. This makes me so happy to have such a generous, involved, helpful community. Sending Full Power Energy Thanks!!!
Be careful with those - if they’re placed in the wrong place they can trigger a “fan assist error” because they stop the fan. Try to keep them out of the path of the back of the head. You can use the thin neodymium ones without much problem or the rectangular ones on the edges (the head won’t travel over them). Or you can get a magnetic shielding metal to glue to their tops (Amazon).
I use them almost exclusively but others are pin used. @Jules is the keeper of the link to the honeycomb pin posting. She’ll weigh in next 
4 Likes
Hey, she’s been out working here… 
1 Like
Thanks! Done and used already!
1 Like