The art of lithophanes has been around for almost 200 years but most people have never experienced the magic of seeing an image emerge from simple white material. The traditional lithophane is cast with translucent white porcelain using molds produced by artists.
Lithophanes can be made using various modern tools and software to turn any photo into a lithophane masterpiece. The CNC router is the tool of choice to create the best lithophanes because it has amazing control that can move a fine cutter in increments of less than .001 inch. Since the lithophane image is essentially a greyscale reproduction that is only .1 to .15 inch thick, the CNC resolution allows for fine details and seamless gradients to create photorealistic images. Making lithophanes with a CNC router is relatively easy but still requires careful photo selection and preparation to create a work of art. I hope that with some tips and superior Candlestone material to help guarantee your success.
I have researched and tested many materials and lighting to find what works best for making lithophanes on a CNC router. While it may seem a simple thing to take a piece of material and carve it into a lithophane, the end result can vary significantly depending on your choice of material. Most people think of Corian as the only solid surface material. In fact, there are many manufacturers of solid surface material and all have different chemical characteristics. While a manufacturers are concerned with suitability for countertops, sinks, etc., our concern is machinability, purity and light transference.
In the quest to find the best lithophane material I obtained samples from many different manufacturers around the world to test and compare. What I found is you want a material that is less translucent than most commercial countertop products. This allows you to better control the light passing through the material and have a higher contrast in your lithophane. Starting with Candlestone will ensure you get the best results.
There are a lot of good guides and tutorials that explain how to make lithophanes with a CNC router so I will instead provide some tips along with links to those guides.
Most people use a small ball nose or tapered ball nose when making lithophanes. In my quest to get as much detail as possible I instead use a 30 degree vbit. The downside to this bit is that the tip is very delicate and I need to be more careful with speeds. When cutting a lithophane, the XY feed rates are almost always limited by the Z axis movements so I set all axis around 80 inch/min to make sure things do not get moving too fast.
I cut the lithophane at a 90 degree angle which both speeds up the cutting and helps to ensure that I don’t break the tip of my bit on the first row.
A very small tapered ball nose would be my second choice. It can be very close the the same detail and is very unlikely to break.
I do not do a roughing pass but instead pocket/vcarve the area for the lithophane first. I make this pocket .088″ deep which leaves me .162″ of material. My lithophane model is .13″ and i leave .03″ of material below the model.
I almost always use vacuum to hold the lithophane blank, even if I have hold downs. Since you are cutting very close to the spoilboard, I believe it helps to ensure you do not break through the back. I also always set me Z reference to the spoilboard. You also want to make sure there is no movement of the blank since this would blur the image.
Cutting can leave very small bits of material in the grooves, especially with the vbit. I use dental tools to scrape anything obvious which is normally sharp edges and the border. I then scrub the lithophane with soap and water and a stiff brush. Most people will probably never notice the difference but I think it improves the look.
Start with a good photo and use a photo editor to convert to black & white first. Perform any necessary adjustments as needed. A great color photo does not necessarily make a great lithophane. Converting to black & white first will give you a better idea of the final product.