Two college students invented an adapter that allows 3D printers to print in full color for less than $100


Credit: Spectrom

3D printing is generally a monochrome affair. Full-color printers are expensive, so the more casual user is likely stuck printing in one or two colors.

Cédric Kovacs-Johnson and Charles Haider, both chemical engineering undergraduates at the University of Wisconsin-Madison, say they have come up with a solution: a sub-$100 device that upgrades desktop 3D printers to print in a full rainbow of colors. They call it Spectrom.

The system is compatible with fused deposition modeling 3D printers that use a standard-size spool of filament. FDM printers melt string-like plastic bit by bit and lay it down in layers to create an object. Spectrom adds dye to the plastic as it melts, allowing printers to shift between colors.

An item printed with the Spectrom device. It's also capable of more gradual transitions between colors. Photo courtesy of Spectrom.

An item printed with the Spectrom device. It’s also capable of more gradual transitions between colors. Photo courtesy of Spectrom.

“What we find really innovative in our approach is we went back to the roots of paper printing and we said, ‘How did they accomplish a range of colors?'” Kovacs-Johnson said. “We can print everything from dark blue to pink to red and everything in between.”

Desktop 3D printer makers have generally gotten around the one color problem by adding more than one print head. botObjects, a desktop printer maker that has been teasing the community for years with its full-color printing abilities, has revealed that its machine works by combining different pre-colored filaments.

Spectrom doesn’t require a specialized printer to work. The idea is that you install it on your existing printer and you’re ready to go. Your computer outputs code that tells the device when to switch between colors, and your printer operates as if it was printing with a regular filament spool.

Charles Haider and Cédric Kovacs-Johnson at the Innovation Days competition. Photo courtesy of Brett Stepanik.

Charles Haider and Cédric Kovacs-Johnson at the Innovation Days competition. Photo courtesy of Brett Stepanik.

The duo didn’t arrive at the method immediately. During a year and a half of development, they tried combining different colors of filament and different dyeing methods. They experimented with both ABS and PLA plastic.

“It was just a whole ton of trials before we looked at something and said, ‘Oh! That works exactly how we thought,'” Kovacs-Johnson said.

Their invention won them two first place prizes at UW-Madison’s Innovation Days competition last month. Haider and Kovacs-Johnson now have a patent pending for Spectrom and are looking at bringing more people onto the team. They are considering working with larger companies or launching a Kickstarter campaign.

Haider said that at the end of the day, they are hobbyists too, and as a result are focused on making sure it is compatible with any printer.

“We want to get it out to as many people as possible,” Haider said.


Glen Searle

The London 3D printer community has been using this method since 2010. The ink used in Sharpie pens on white filament works best, there’s also open-source automated colour applicators, search Thingiverse for examples.


nothing against this guy, great development, but I hope they didn’t get the patent.

For me it seams like an automatic version of this

Patents like this could block the development of 3D printers for another 20 years :(

Johannes Schriewer

Patented? Oh come on… another innovation brake.

Eric Moreau (

Genius, I want it on my Fortus 250!


can i know the model of printer that it can be used with?
hope it is stereolithographic.


not very likely. they’d win more than a college innovation prize for doing that. imho.

Marcelo Ruiz Camauer

how quickly does it switch colors? can it do WITHIN a layer? otherwise it’s no better than botObjects and not that interesting… can we see more sample objects?

Ken Dix

good question! Sure it’s capable of more gradual transitions, but how distinctly can it switch colors?


the sample object looks layer by layer, so it should be able to do that, at least. hopefully, finer control is only a matter of software…

Signe Brewster

Haider told me it can switch within a layer. A University Wisconsin article about Spectrom details just how exact they are looking to be:

“Possible applications of Spectrom include creating color-matched prosthetics. Whereas currently, doctors hand-mold prosthetic body parts, such as noses, then afterward, an artist matches a patient’s skin tones, Kovacs-Johnson and Haider envision the process taking far less time and money. “With 3D printing you have the ability to scan someone’s face and build an exact face profile,” says Kovacs-Johnson. “You can then print off, using Spectrom, a nose that would match their skin exactly.””

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