Grayscale Color-Coding
Amanda D’Amico’s sample book
Oh, that sinking feeling when I check the time of a job on the laser cutter and it comes back twice as long as I expected. Even with all my experiences I've learned never to guess how long a job will take.
The final project for July's online Laser Cutting for Artists course was a custom material sample book using the files participants created during the course. While I loved seeing each book come together and how different each artist's images were, they took much longer to produce than I expected!
There came a point when I had to look for more efficient ways to produce the laser engraved pieces, specifically the laser engraved fabric. Grayscale color-coding to the rescue!
In this post, I share with you how grayscale color-coding can cut engraving time in half.
Material & Technique
For this method, I used Jackson fabric by Premier Prints. It is a durable silkscreened cotton fabric that holds up well to laser engraving. While you can achieve this effect with some heavy weight dyed fabrics, the advantage to silkscreened fabrics is that the color doesn't permeate as deeply into the fibers making it easier to engrave without overly compromising the integrity of the fabric.
Standard Color-Coding
In laser cutting, color-coding is used to program the laser cutter to engrave at different depths in a single piece. For example, in this image (right) the black areas will be set to engrave at a higher setting vaporizing more material and the red areas will be set to engrave at a lower setting removing less material.
The challenge with this method is that the laser engraves in two passes. Firs, it engraves all the black areas, then it goes back and engraves the red. Two passes = double the time.
Grayscale Color-Coding
With grayscale color-coding, the fills in the vector image are color-coded with percentages of gray. **
The power level the laser cutter is assigned to pure black and the laser cutter automatically adjusts the power based on the value of gray. The lighter the gray the less power the laser fires.
** Grayscale in this context is not to be confused with a grayscale raster image (JPEG, TIFF). These are vector images where the fill is a percentage of gray instead of a color.
The advantage of this method is that the image engraves in one pass. An image with two engraving depths that takes 30 min with standard color-coding only takes 15 min with grayscale color-coding!
Pros and Cons
If it takes half the time why would I ever use standard color-coding? For me, it is a question of which is more important for a particular job: time or specificity.
While on some machines you can adjust the algorithm for grayscale color-coding, ultimately you don't have as much control over the settings. For jobs and materials where fine tuning the settings is needed I choose standard color-coding. For jobs were time or cost is most important I use the grayscale method.
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