DIY dichroic (dual-color) filament

There’s a new trendy material on the market following the extremely popular “silk” materials, and maybe you’ve seen it, material that “changes color” when viewed from one side or the other, because the filament is actually two colors split down the middle like that dual color toothpaste.

This isn’t a new concept, and the material is quite expensive, so here’s some tips and a DIY alternative.

First off: due to cost, to conserve material it’s wise to print in vase mode, which restricts the body to a single extrusion line tracing the perimeter of the model to produce a weak but beautiful print.

Vase mode has two advantages considering the special properties of this material:

Economy: you can’t get much less material for a given volume than vase mode, single solid base, single perimeter wall, no top.
No layer transitions: those normal “zits” on each layer where the permitters cross don’t appear in vase mode because the filament is built up in a continuous spiral.

Finally, to show off your dual color prints, they’ve got to be spinning, it sounds silly, but nobody is going to notice that some object on the shelf is green when you stand on one side of the room and blue on the other, unless you point it out explicitly. Rotation draws the eye and you immediately notice the obvious transition.

I mentioned this isn’t a new concept, it was briefly marketed commercially by FilaBlend and reviewed by none other than Matt Shultz way back in 2018, and twitter user @DasMia3 has another approach where you literally print a spiral and swap colors halfway through the print to produce a 9.5M coil of material.

Color Gradient Hexagonal Filament - DasMia (PrusaPrinters link)

Example prints using FilaBlend Materials

(courtesy of FilaBlend)

By creating your own filament, you produce unique combinations beyond what’s on the market and it’s even a good method to use up scraps of nearly consumed rolls since you need less than ~5M of each input color to produce a 9.5M coil of dual color output.

It’s advisable (thanks @DasMia3) to use high-contrasting colors for best effect, and I concur: my first test was a deep purple and forest green “pearl” PLA combo and the effect is visible, but not obvious.

My next test was an improvised combo of Filament-PM Pearl Blue PLA and Filament-PM Yellow PLA, which produced a striking green in the vase which is quite mesmerizing in motion.

You’d think that using DIY filament way out of tolerance would be an issue, but it isn’t, in our experience you need to under/over extrude by a significant amount to really compromise the look and function of a print.