Prusament PETG Ultraglow Green – the brightest glowing filament on the market!

Halloween season is long gone, but the days are still short and nights dark. It’s time to brighten them with our brand new glow-in-the-dark Prusament PETG. Please welcome PETG Ultraglow Green! The brightest glow-in-the-dark filament on the market, suitable for both visual and functional components.

Full of glowing powder

Q: How much glowing powder did you put in it?

A: Yes.

First things first: How does glow-in-the-dark filament work? Certain materials absorb light energy and then emit light at specific wavelengths. You’ve almost certainly encountered those materials before – in various safety signs (emergency exit), toys, or illuminated watch displays, and more. While phosphorus was historically used for this purpose, modern alternatives rely on strontium aluminate due to its superior safety profile.

Strontium aluminate is non-toxic, non-radioactive, and doesn’t react with water or other common chemicals. You can charge it by exposing it to a light source, such as a strong LED, a bulb, sunlight, or UV light (which is most effective).

We took clear Prusament PETG and filled it with a strontium aluminate powder, as much as physically possible. Seriously. Turn off the lights, and your prints don’t just glow – they illuminate the room with a dim, and super spooky sci-fi green light. This is nothing like the little glowing stars barely visible on the ceiling we all know from our childhood. We grew up, and our toys grew with us… 🙂

Glow properties

We really tested the limits again. The Prusament Ultraglow is filled with the highest possible amount of strontium aluminate powder. It’s the maximum we could achieve while maintaining reliable printability and delivering exceptionally bright luminescence. We felt like there was no strong reason to make another mediocre glow-in-the-dark PLA filament, as the market already has plenty. Instead, we did what we do best: we took it up to eleven.

Sure, anyone can slap a fancy claim on the packaging, so we want to prove it to you: we ordered other branded glowing filaments and put them all to the test. We’ve kept the other brands anonymous, as the results speak for themselves.

We printed a good ol’ benchy with each filament, then charged it with a 405 nm UV-light source (CW1S) for 20 minutes and photographed the glow intensity. You can see the result below: Prusament PETG Ultraglow shines by far the brightest when compared to common glow-in-the-dark PLA.

Glow intensity comparison.

Measured luminance of Prusament PETG Ultraglow Green over time

Price, weight, and color

PETG Ultraglow is currently available in green, with additional colors on the way. One 800g spool costs 82.99 USD (import duties included) / 69.99 EUR (VAT incl.).

Printability

We want to be clear and transparent: some things come at a cost, and the Ultraglow is exactly the case – and we’re not talking about the price. Strontium aluminate is the hardest material we ever used. It is highly abrasive, and it would be naive to think that a filament filled with such an additive would be as easy to print as common PLA and PETG. As always, we did our best to make it printable as easy as possible, but there are several things you should take into account:

A hardened nozzle is mandatory! This is the most abrasive material we’ve ever made – it acts almost like a “liquid sandpaper,” and we can even see increased wear and tear on our manufacturing equipment. It will destroy your brass nozzle in no time.
You may see accelerated wear on PTFE tubes and hardened components with high-volume use. This includes hardened steel nozzles and Nextruder gears. Occasional printing won’t be an issue, but regular high-volume use will shorten the lifespan of metallic components. If you want to be 100% sure, you can use the E3D DiamondBack nozzle, which is harder than strontium aluminate and won’t wear out.
A 0.6 mm nozzle diameter is recommended. While we provide 0.4 mm profiles, we strongly recommend larger diameters to prevent clogging. Standard (non-high-flow) nozzles work better for this material.

For detailed information about print preparation, such as setting your XL and lowering friction in long PTFE tubes, see our online help article.

Examples of use

Most glow-in-the-dark 3D-printed creations are toys, art, and often Halloween-related decorations. While we absolutely love seeing your creative projects, we deliberately chose PETG as the base polymer for a reason: it’s stronger than commonly used PLA and resists higher temperatures, making it suitable for functional parts.

And you can take it further with the XL and other multimaterial solutions. Print functional models in standard PETG and add glowing accents to highlight specific components – switches, handles, indicators, or any part that needs visibility in low light.


Visual parts, toys and props (Glowing alien by Prusa)	Safety signs and guiding arrows (glowing Emergency Exit Sign by The Kit Card Guy, Skirting Arrow by SteveW91 and Diving arrow by Jakub Kočí)

Glowing parts to prevent losing (Nordic Knurled EDC Capsule by DFV Tech and Mix of models by Prusa)	Glowing frames for doorlocks, light switches and more (Glow in the dark doorlock finder by Ronny)