I know I am missing something. When I size my image file (NOT VECTOR) in Photoshop and save it as a jpeg, png and others, the size that loads onto the glowforge workspace is different, usually much larger (2X or 3X the saved size)
What simple, setting is there to be confident that the size is exactly what I saved in Photoshop.
Also, while I am asking, what is the trick to perfectly aligning 2 pieces of artwork in the glowforge workspace. i.e. an image file and a cut file
Set the DPI of the image to 96.
Position the elements the way you want them in your design program, and upload them already aligned.
Thanks. 96dpi is so low rez. (dot size is the same as screen printing!) I will try.
I thought that was the answer…I have recurring cutting rectangles, squares, circles, etc on file that I tend to load separately with my artwork. Right now I am enlarging the image in glowforge and aligning by eye.
It’s a laser cutter, not a photo quality printer.
Then definitely run the camera calibration routine to get your visual alignment as close as possible, and use the “set focus” tool at the location you’re visually aligning.
The Glowforge is capable of a lot more than 96 DPI. This can be a confusing topic because it gets used in two ways. There’s the pixels per inch in a bitmap file, for which 96 is indeed very low, and there’s the way programs like Inkscape use “DPI” in their SVG files, where they are scaled such that 96 represents an inch, but things can be positioned much more precisely with decimal values.
I haven’t done the experiment and I don’t know if the Glowforge software pays attention to things like embedded resolution in PNG files. I believe you’re better off using an SVG or PDF with the image embedded in it.
DPI and PPI are very different animals. It seems that 96DPI is very low rez especially using photos and trying to use vary power for 3D attempts. But the size issue is still a question. Sometimes png holds its size and sometimes it does not. There is no “save as” svg in photoshop. I do not usually like to work in Inkscape…just Illustrator and Photoshop
There is a short explanation of the differences at the link below…but the bottom line is, if you drag the Photoshop PNG image into one of the vector drawing programs (Illustrator, Inkscape, Affinity Designer, etc.) , size it correctly there, embed it and then Save it as an SVG format file, the Glowforge interface will size it correctly, and it will have the same high PPI content. (You are just setting the size in one of the drawing programs.)
What Jules said. You can’t use raster image file dpi for accurate sizing in the GF UI. The machine can print down to 1355, which you would never use. Just think of it like a printer, and include enough resolution to give a clean image. If you wanted a 4x6 photo print, you wouldn’t upload a 400x600 pixel image, more likely 1200x1800 or better. Same applies here.
Then embed it in an SVG using your design app of choice if you need accurate sizing, or use the rulers in the UI for “good enough”.
Thanks for the answers. I was trying to go from PS directly to the GF UI. Based upon the suggestions above,I plan to change my workflow and go from PS to AI and precisely size the image and save as svg. The remaining question of PPI might still be an issue. i.e.with my pro-printers I aim for 360 or 300 and occasionally 240. at 100%. What is the optimum PPI for GF?
That’s going to depend a great deal on what you’re doing with it. Material, power and speed, LPI, greyscale mode, etc., will all make a difference. Probably the only way to get the right answer is to experiment a bit.
That’s a tough one to answer since you’ll likely be printing at different output resolutions depending on the project, which I don’t think one normally does (at least often) with inkjet printing. That said, I use a minimum of 300PPI for projects printing at 270 LPI or under (most commonly use 225 or 270 for photos). If above 300 LPI, I tend to match the desired LPI.
I also never use the GF app to resize images. I never tested it extensively, but just like photo printing, the sharpening is very specific to the print size. Once you resize, that sharpening goes out the window. And laser processed images really like a good amount of sharpening.
I’ve never seen evidence of there being any, although I’ve never intentionally tested to try and find one.
Reverting to the print analogy, I just ensure my image has enough detail for the final output.
Very different critters with very different needs. You could take a photo of a symmetrical item on a hazy day and the mirror and blend so the back is darker than the front so the front will be higher.
You can also play serious games to accomplish the same goal , or use a photo to 3d App like Meshlab that actually creates a 3d image as part of the process, and then can put out a height based grayscale image.
However if you take a normal photo of say a person with the sun on one side of their face, the sunny side will raise up and the shadow side will be a pit with the result very strange.
Agreed. Missed that comment earlier - 3D Engrave is not suited to “typical” photographs, more for depth-map style graphics or enhanced photos.
Missed that x3.
Vari-power is immensely tough to make work on photographs. It’s not really my style for engraving - I like the printed on look typically.
Material only holds so many shades of burn. When you use vari-power to engrave a photo, you’re basically reducing the image to a X-color GIF (say 6-color GIF). And then the edit and power settings need to be perfect in that the grayscale values need to be hitting those different speed/power/LPI sweet spots (to get the different shades) just right.
The more successful 3D photo engravings I’ve seen tend to be edited to be “comic-like” in that they have very exaggerated features. In Photoshop, you’d probably want to look at things like the emboss filter (and then additional editing) to accomplish that.
As for convert to dots, which is really dithering. It uses just on or off to produce dots. The lighter the value, the further the dots are; the darker the value, the tighter the dots are. Our brain perceives those as shades. You can hit a lot more perceived shades with dithering than you can vari-power.
In the end though, you can hit some really photo-realistic engraves with a laser.
Hello. Thanks for all the responses. I have learned a lot and also have confirmed image/engraving answers I suspected was the case . When I had a Universal Industrial laser I used a program called Photgrav that converted photos for “3D” engraving. It worked very well, but I discovered I was able to achieve the same results with photoshop filters and conversions. jbmanning5 thanks for your insights and suggestions. Only certain of the Proofgrade materials offer the 3D option. For example with draft board the 3D option is offered. I have tried a number of graphics and have found that the Proofgrade setting is way, way off.
3D Engrave is also available with Proofgrade acrylic and hardwoods. Any solid material.
The reason it’s not available with plywood is that there is a different core material, so the results are not consistent as it burns through the different layers.
It’s just a setting that uses “vary power” as opposed to “dots”, and you can use it on whatever material you choose.
Thank you to everyone on this thread, your help is much appreciated!
I’m glad you got the information that you needed! I’m going to close this thread. If you run into any other trouble, please start a new topic, or email us at support@glowforge.com. We’re here to help!
