I've been using matboard in a laser cutter for a while now because of how great the contrast is and how easy it is to create some great signage. With this project, I wanted to try to cut an image into matboard and preserve as much detail as possible.
I decided to use a friend's birthday as an excuse to do the project, and since he collects vinyl records, album covers were the obvious choice! Note that this technique can be used for almost any image.
Note that the final product is lighter in color than the first two images above, I took those pictures in poor lighting. The third picture is a better representation of what the final product will look like in normal lighting.
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Step 1: Gather Materials
Things needed for this project:
- Matboard (I used white-core matboard with a black finish) which I found at my local art store:
- Terminology (core/finish). In my experience, matboard is made by creating a single sheet of uniform color (likely white). This sheet is what I refer to as the core and is the thickest part of the board. To create different colors of matboard, a very thin outer sheet is glued onto the core - I refer to this outer sheet as the finish. By laser-cutting through this thin outer layer - we reveal the inner layer which is a different color.
- The matboard comes in 32" x 40" sheets for around $20. The image above is just a section of it to show the color contrast.
- You can buy the matboard from anywhere, the only important thing is to make sure you get something with a white-core and black finish (so you can laser-cut through the black finish to expose the white). If you buy black core with a white finish, just skip the invert color step (first part of step 7).
- As a future project to try out, you could use any color matboard as long as the core is a different color than the finishing.
- I used a 120 watt Epilog Laser Cutter
Step 2: Choose Your Image(s)
I decided to laser cut some album covers for my friend who collects vinyl records. I choose his two favorite albums (Wish You Were Here by Pink Floyd and Deja Entendu by Brand New).
The larger the image size, the better it will look in the end. Try to choose an image that is detailed enough so the resize process in the next step will not destroy the image quality. I used the following sizes for the images:
Wish You Were Here: 1280px x 1024px
Deja Entendu: 1425px x 1425px
Step 3: Resize/Resample Image
This is important for the later steps. Make sure you know what you want the final size of your image to be.
Start by opening the photo in Photoshop. Then select Image -> Image Size... (Alt + Ctrl + I). You will see the dialog box in the image above.
Next, change the values of "width" and "height" for the "Document Size" section to whatever you want your final image size to be. (I did 15inx12in for the first, and 12inx12in for the second)
Enter the resolution for the final image (I used 600 pixels/in). Note this value - you will need it for later.
Next, choose which resampling method you want Photoshop to use (ensure the "Resample Image" check-box is selected).
- Bicubic Smoother - Best if your original size is smaller than your final size (this is the one I choose for the first image since the image file was smaller than 15inx12in)
- Bicubic Sharpener - Best if your original size is larger than your final size (this is the one I choose for the second image since the image file was larger than 12inx12in)
If the resized image is extremely pixelated, consider getting a new image. It doesn't have to be crystal clear, but clear enough that you can make out the details after zooming out.
It is also a good idea to create a smaller version of the image here (2-3") and follow all the same steps. This will give you something to do test cuts with and ensure you have the right settings without wasting a bunch of material.
Step 4: Apply Photoshop Filters: Unsharp Mask
The goal here is to get the photo ready to laser cut. We cannot cut the photo as-is because the laser cutter will not fully remove the black and will burn the outer layer.
To get the image ready to cut, we have to convert it to a bitmap image (an image made of small black and white dots which - when zoomed out - combine to create a black and white image). Before that, applying some Photoshop filters will help bring out the contract in the image and make for a better cut.
Almost all of the steps I take here are based on the steps in this document. I had to skip a few steps/change some of the values to get it how I wanted before the cut. Nothing I am about to say is an exact science and I am nowhere near a Photoshop expert, so it might take some messing around with before it is ready.
This filter helps create contrast and clear up the blurred areas.
Select Filter -> Sharpen -> Unsharp Mask (You should see the menu in the image above). I used the following settings:
- First image (Wish You Were Here)
- Amount: 500%
- Radius: 5.1 pixels
- Threshold: 6 levels
- Amount: 500%
- Radius 7.0 pixels
- Threshold: 6 levels
Like I said above, these are not exact values. Play around with it until you get clear lines and good detail in the photo. I usually like to set values for amount and threshold, then adjust radius until it looks appropriate.
Step 5: Apply Photoshop Filters: Sharp Mask
This filter will bring out the edges of the photo. Select Filter -> Sharpen -> Smart Sharpen... (You should see the menu in the image above). I used the following settings:
- Settings: Default
- Amount: 500%
- Radius: 2.5px
- More Accurate checked
I choose to use a very slight filter affect here. I was already happy with the look of the image, so I didn't need much extra contrast with this filter. If your image still lacks contrast, increase the radius value.
Step 6: Convert to Bitmap Image
Convert to grayscale
Before we can create a bitmap, we have to first convert the image to grayscale. Select Image -> Mode -> Grayscale. Click "Discard" in the dialog that appears.
Select Image -> Mode -> Bitmap (You should see a dialog box like the one in the image above).
Enter a value for the "Output" field. This is the step where you should use the resample value from step 3. The output value should be the same as the input value (both are 600 pixels/in in my case). The method used should be halftone screen. Select "OK"
You should see another dialog box appear that looks like the one in the second image. Enter 200 lines/inch for frequency. Select "OK"
Step 7: Invert Image Colors / Export Image
This step is only necessary if you have a black finish on a white-core matboard (or any matboard with a dark color on top of a white-core). Since all the black areas will be engraved, we need to swap the colors so the image will engrave correctly.
Select Image -> Adjustments -> Invert (Ctrl + I)
Export the image so it can be cut. Use File -> Save As... to save the file as a png.
Step 8: Cut Away!
Import or open the file in whatever program loads the laser cutter's jobs (in my case it is Illustrator). It may look a little strange in the new program (when I imported the photo I could clearly see the dots, which did not show up in Photoshop - not sure why this happens)
I used the following settings (but they will differ based on the power of the laser cutter)
- 30 speed
- 15 power
- 100 speed
- ?? power (see below)
- Stucki Dithering
For the power settings, it was variable throughout the cut. Luckily the machine I am using allows you to change the power while rastering. I used this to my advantage to make sure the image was well-cut. I started around 50% power, and kept an eye on the depth/detail of the cut. If it was going to deep and losing detail I would decrease the power. If there was too much black left on lighter areas of the image, I would decrease the power.
If you are not sure on the speed/power settings, use the smaller image from step 3 to do some test cuts and hone in the settings to get a perfect cut.
Step 9: Ideas for Further Improvement
- Perfect the Photoshop steps - all of my experience is by visual observation
- Try this method using a different color of matboard
- Find a way to clean up the burning so the white does not fade (right now, the cutting process slightly burns the matboard and leaves the white darker than the original color).
- As an alternative, find a piece of matboard that has a black core with a white finish - this should eliminate the problem of the white layer getting darker.