The Hidden Feature in Translucent Polymer Clay

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Optical brighteners are fluorescent dyes that take invisible UV light and reflect it back in the visible spectrum. If something contains this dye, you will see it brighter than if it didn’t. This dye is used in laundry detergent, whitening toothpaste, and printer paper. It’s an additive that makes white things look, well, whiter. And you guessed it, these optical brighteners are used in some brands of translucent polymer clay to make them look brighter (learn more about this here). But not all brands of polymer clay contain this dye. Read on to learn why this is important when creating with translucent polymer clay.

Why This Matters

Translucent polymer clay tends to turn a bit yellow or amber when it’s baked too hot. So many manufacturers add this optical brightener to counteract the yellowness. That sounds like a great idea, right? Just like your white undies, nobody wants things to look yellow. Well, sort of.

Yellowing isn’t Normal

First, let me assure you that translucent polymer clay shouldn’t turn yellow when you bake it. If it does, your baking setup needs to be addressed. (Newbies get such bad info out there. No, this color change is not normal and can absolutely be avoided. If you’re struggling with your baking setup, go here.) The exception is when you’re using Sculpey III or Kato Polyclay translucent. Both tend to discolor badly, even when baked properly.

It Makes the Translucent Look Whiter

While nobody wants yellowed translucent, nobody wants it to look white, either. Too much light reflecting from your translucent project can obscure the light coming THROUGH your project, and it’s that light which makes it show depth and translucency. You can see this effect here.

comparison of optical brighteners in baked polymer clay
The top pieces were made with Pardo Agate. The bottom pieces were made with Pardo Art Clay using the Watercolor Agate technique. On the left, they’re shown in natural light (near a window). On the right, they’re shown in artificial studio lighting.

Note how the pieces on the bottom look whiter and more cloudy when they’re shown in natural light (bottom left). The optical brightener makes the translucent clay glow bright white, obscuring the depth that makes the pieces look much nicer in studio lighting.

Remember the strips from the video above? They look identical in studio lighting, as you see in the video. None of the pieces have yellowed during baking. But look at how they appear when I photographed them in front of my kitchen window. The one on the left suddenly looks more yellow by comparison because the other two are glowing brightly. Note how the ones with brightener look more white.

Strips of Pardo and Cernit polymer clay showing that Pardo Agate is more yellow in natural light.
Pardo Agate, Pardo Art Clay Translucent, Cernit (L-R), showing the way the clays appear in natural light.

The Glow is Visible

Have you ever noticed that liquid laundry detergent has a funny blue glow? It just looks, well, weird. That’s the light being reflected back by the dye. It’s a weird violet color. And that glow can show in your polymer clay work. If your item is made with cool colors, the violet glow of the optical brightener will be harmonious. But if you are using warm or natural colors, the violet will clash, making it look pasty. You can see what I mean here.

Optical Brighteners in polymer clay can make a difference in your project. Does your clay have this fluorescent dye? Learn more at The Blue Bottle Tree.
You can see the effect of the fluorescent dye in this picture. The bead was made with Premo White Translucent. The picture on the left was taken in indirect natural light outdoors. The picture on the right was taken in a lightbox.

The Two Premo Translucents!

Not all translucent polymer clay brands have this optical brightener dye added to them. In fact, this is the only difference between Premo Translucent and Premo White Translucent. Yes, there are two types of Premo translucent. Contrary to what is continually repeated and stated in Facebook groups, these clays are the same color and have the same translucency. In fact, the dye is the only difference. Here they are, side by side, in studio light and then with a black light (UV) flashlight applied.

photo comparing Premo Translucent with Premo White Translucent under black light.
Premo Translucent and Premo White Translucent, under studio light and also with black light (UV) applied.

If I take these circles of Premo to a north-facing window or under a shady tree on a bright day, the Premo White Translucent will look much brighter and whiter. If you’ve ever noticed there’s a difference between these two Premo colors, it was likely due to the light shining on them. If there’s a lot of UV light in the mix (like natural light has), one will look much whiter. Try it, you’ll see what I mean!

Which Brands of Translucent Have Brightener?

So which brands of translucent polymer clay have optical brightener included in them? How can you tell? It’s easy to see the glow of the optical brightener fluorescent dye by looking at the clay under a black light. You know, the special light bulbs used to make aquariums glow blue or that are used at parties or during Halloween. You can buy UV flashlights for “detecting pet urine” or, ahem, other substances (Affiliate Link – learn more here). You could even use the light from your UV lamp that you use for curing resin.

Translucent Brands With Brightener

  • Premo White Translucent
  • Cernit
  • Fimo Effect
  • PVClay
  • Prism & Pro
  • Pardo Professional Art Clay

Translucent Brands Without Brightener

  • Premo Translucent
  • Kato Polyclay
  • Pardo Translucent Clay (Agate)
  • Sculpey III

What to Make with Translucent?

Whether you have Pardo, Premo, or Cernit on hand, they’re all perfect for making Watercolor Agate. You can see my “in-progress” shots at the top of this article. But here’s what they look like all finished. I LOVE them!

Blue watercolor agate earrings.
Blue faux stone earrings made with the Watercolor Agate tutorial.

And now you know the secret to choosing the right clay for your project. I love using Pardo Translucent Agate, Cernit, or Premo Translucent for this technique. Of course, if I’m making warm tones, I prefer to use Premo Translucent without the optical brightener, like these.

And if you want to learn how to make these earrings and learn the tricks for creating these faux stone looks, here’s how you can do that. Have fun!

Foolproof and versatile

Often imitated, this original course is a deep dive into the process of making ethereal translucent faux stone.

3 thoughts on “The Hidden Feature in Translucent Polymer Clay”

  1. Roxanne Parsons

    Great info! I’m experimenting now. Just ordered the blue light for more sciency trials! Thanks, Ginger.

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