Letterpress Goes 3D: Preparing a Born-Digital Image for 3D Printing for Letterpress

TinkerCAD is an intuitively designed and effective means of making a 3D print from a 2D image, and thus ideal for creating letterpress blocks. With that said, there is still a process of prepping an image to be 3D printed using Illustrator, and often Photoshop. If you are new to Photoshop, you will likely have a much easier time creating a 3D print of a digitally produced, purely black and white 2D image (say, a logo) than a very detailed historical image. Historical images require touching up that can take some time, especially for those not comfortable yet with Photoshop toolkits, and an often lengthier vector clean-up process. Factor that extra time in when creating historical replications. This guide will not address Photoshop cleanup, and instead will begin with Illustrator, with the assumption that you have a clean, black-and-white image.

Regardless of whether the image you choose is digital or analog-born, make sure that it has clear, relatively thick lines that can be detected by Illustrator and TinkerCAD and of a fidelity that can be 3D printed. Hyper-detailed etchings with very thin lines WILL NOT 3D print properly.

Refer to the video below, and/or read through the following guide!

1. Ensure your image is saved as a PNG or JPEG.
2. Open your image in Illustrator. 
3. Select View > Transparency Grid to enable transparency. This setting will ultimately allow you to be sure the proper elements of your image will be raised for printing.
4. Reflect your image so that it prints properly; the 3D model should have a flipped horizontal rendition of your image. Right click the Image, and select Transform > Reflect.
5. The default reflection is Vertical, 90 degrees, which is the setting you want. Click ok if it appears that your image has been flipped across the Y axis.
6. In order to create a 3D model of the image, it must be vectorized. A vector image is computationally processed so it can be resized to any size without losing detail or becoming blurry. To make the image into a vector, use the “trace” function in Illustrator.
7. With the image selected, navigate to Object > Image Trace > Make. 
8. This will create a basic trace. To tweak the tracing, go to the right column and click on the icon that looks like a menu window with two lines on it. A menu will open up. First, change the trace from “color” to “black and white,” even if your image is already black and white. 
9. After that, the area to pay attention to is the slider named “threshold.” Adjust this slider until the trace matches the original image, or perhaps more accurately, what a clean rendition of the original image would look like. Click on the “advanced” arrow and manipulate the other sliders to further impact the resulting image.
10. Finally, check the box that says “Ignore White” to turn the white space transparent. This will enable the 3D modeling software to properly detect the parts of the design that should be raised in the print.
11. When done, click “expand” in the right hand column. This will finalize the trace.
12. When you are done, save the image as an Illustrator file for later reference — tweaks are sometimes needed. 
13. Finally, save the image as an .SVG file which can be read by 3D modeling software. Make sure to select SVG 1.0 in the menu that pops up when you select save as SVG. DO NOT export as an .SVG, this will cause an error. Specifically save as an SVG so you can select the proper SVG 1.0 filetype.
14. You are ready to move on to TinkerCAD!
15. Go to TinkerCAD.com and create an account if you do not have one already, or sign in if you do.
16. Start by importing the SVG file you just made. Please note that the following images utilize a different image than those preceding, but the process is the same.
17. Resize the 3D model generated from the SVG file. Click on the 3D model and then on one of the boxes on its corners. Measurements will pop up, in mm. Change the measurements to the desired size (you can use google to easily translate between font size, inches, and millimeters). 
18. Once the model is the desired size, add a box into your workspace. 
19. Resize the box to be the same width and length as the 3D model of the image you imported using the same method as above.
20. Select “workplane” on the right hand toolbar. The workplane allows you to stack objects on top of one another. With the workplane cursor active, click on the top of the box you just resized so that you can stack the 3D model of the image onto the woodcut.
21. With the workplane in place, click on the 3D model of the image and press “D.” This will set the model’s height to slide neatly on top of the box with the workplane on it.
22. Move the 3D model of the image to be flush on top of the box. Zoom in to ensure that the edges of the two boxes are flush all the way around — it can be easy to miss slight misalignments if you do not zoom in!
23. With the two objects, the box and the model of the image, flush together, click and drag to create a selection area including both objects. With both objects selected, click “Group” on the upper toolbar. This will group the objects together.
24. Select your grouped objects so that you can see their height measurement. Adjust the height to be 23 or 23.3 mm — just under type high.
25. You’re finished! Rename your file in the upper left corner, and select export. Save the file as a .stl for printing. It can now be sent to your 3D print space for printing!