How do folks generally find the right settings to use on the small lasers?
It seems like one approach would be using Corel Draw to make a test grid with a row of different intensities of black (say 10%, 20%, 30%), a row of different intensities of green, blue, red, cyan…
And then configuring the printer settings so that black is 100% speed, green is 90% speed, etc.
Does someone already have a Corel Draw file set up to do this?
Is there a better method?
It’s not even clear to me that I can get different intensities of colors other than black in raster mode. If a 255,0,0 pixel is 100% power red, is 128,0,0 50% power red?
One thing that I discovered: if you’re rastering bitmaps, make sure the raster settings are not set for Black & White. I was trying to do squares of 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, full power to see what a particular combination of power and speed did, and I was only getting half of my squares to etch at all, and they all looked the same.
I haven’t gotten a bitmap with color information to do anything with raster. It seems to only consider grayscale. I was hoping I could at least color sections of a single bitmap with pure red/magenta/green etc. and have it etch at the power set for that color, but no luck.
Since no one else piped up, I’ll offer my perspective. Sorry it’s a month late haha.
Trial + Error. Your media will vary from batch to batch. Some days the laser won’t be operating at full power and you’re the one who finds out.
So document your findings, but don’t just blindly enter what worked last time. Always do a test cut/etch.
You might be better off finding out what the defaults are, making a spreadsheet and creating a color palette in Corel from that. Then you don’t need to mess with the machine if your swatches are labeled.
If that isn’t possible then the method you described is how I would do it. Once I confirmed it worked I would create a Corel palette with the swatches you used. Save that palette file and you can load it on whatever computer you’re designing on.
I think I may know why you’re getting that result, but TBH I gave up on Blue months ago so this is just a guess based on what I know from working in digital art and printing for most of my career.
I have always disliked when graphics software, copiers, RIPs and other tools use the term “Black and White”
I would argue that they should call it “max contrast” or “one-bit” or “binary” or something, but no one asked me 
I assume this option processes your image by deciding at every pixel something along these lines:
if (pixel.brightness >= 50) {
changePixelTo(black)
} else {
changePixelTo(white)
}
Please someone correct me if this assumption is wrong!
I think that would explain half of your squares etching, and all looking the same… but it doesn’t explain why different speeds gave the same results. Take all this with a grain of salt, because I always found Blue’s software and hardware interfaces confusing. Hopefully someone more familiar with the machine can set the record straight.
Yeah, any color raster image would need to be converted to greyscale, either by you or the RIP.
I guess it’s assumed that you’re making cuts with your laser and you must have access to vector software. Which makes sense, There are so many color spaces and palettes I would always prefer to use a raster program to dial in the contrast for photos, and for solid fills I would be working with a vector program anyway instead of exporting raster art.
Hope that helps!
I think your assumption is right. I think that when you etch a bitmap, the laser is in one of two states for each pixel: firing or not firing. I think it does not modulate the power for each pixel.
The Black and White setting has a hard cutoff at 50% gray.
The Error Diffusion setting uses an algorithm based on how different the current pixel is from black or white to affect the decision for later pixels (Error diffusion - Wikipedia).
I would assume that the Halftone setting converts the grayscale image to a pattern of black dots of different sizes, but I haven’t actually tried it.
Yeah, any color raster image would need to be converted to greyscale, either by you or the RIP.
I was hoping that it would treat RGB as three different channels of grayscale, so [255,0,0] or pure red would fire at the Red setting, and [128,0,0] or half red would fire as if it were 50% of the Red setting. [0,255,0] would do the same for Green, and so on.
Without that, it seems like to make a chart of power/speed, I need to do a separate print for each power and speed combo.