Could someone tell me if I import a Image (not sure if type would make a difference such as JPG/BMP etc…) and say it comes in at 6"X10" at 250 dpi and I resize to 3"x5" using Jarvis will lightburn automatically adjust the smaller image to 250dpi? I ask because the previews I’m getting for each size look somewhat different.
This is 6x10"
This is 3x5"
The DPI setting is the output resolution to be sent to the machine. If you make a 2" square at 100 DPI, you’ll get an image that’s 200 “dots” across / high. If you stretch that image to 4", you’d get 400 dots. The first preview you’re showing has more dots, because it will be physically larger.
Thanks Oz. So in reality if I were to burn those two images side by side they should look similar since the DPI is the same for both even though the sizes are different?
Yes. LightBurn internally resamples the image to the output size, then dithers, so the larger version should have comparable shading to the smaller version.
If I were to make my image changes in something other than Lightburn like Gimp and select “pass through” then adjust the image size Lightburn would keep the DPI regardless of size because its going to keep the original image properties correct?
Not quite - DPI is a function of the number of pixels in the image and the size it is being output. Pass-through means “send every pixel in this image directly to the laser, untouched”, meaning I am no longer allowed to resample it.
If you have a 200 DPI image, that’s 2" square, and you resize it up to 4", normally I would resample it and output it to whatever your layer setting says to use. With pass-through, I can’t do that, so scaling it up means you now have a 4" image with 100 dots per inch instead of a 2" image with 200 dots per inch. The data sent to the laser will always have the same number of dots / lines as the original if you have pass through enabled, regardless of size.
This is one of the biggest reasons I wish people would at least do the final dithering stage in LightBurn, instead of using the scripts or online tools for it, because once it’s dithered, you can no longer rotate or resize the file without ruining it. (rotation to anything but a 90 degree multiple also requires resampling the image)
Understood. Thank you for that detailed explanation! I have just recently started to adjust my images in Lightburn rather than using scrips. Would you have any suggestions as a good starting point for “cut settings” or “shape properties” numbers for a 2.8w diode?
A general starting point:
Cut settings:
Shape Properties:
Every machine will be different, so you’ll need to play with these no matter what, but that should give you something to start with.
Awesome! Thanks Oz. I will give those a shot tomorrow and report back.
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