Does Resin Yellow Over Time?

One pretty common question we see about resin pieces is whether they’ll turn yellow over time. And yes, they inevitably do. It's pretty much the same thing as those tree resin fossils (Figure 1) with mosquitos or spiders stuck in them from millions of years ago.

Figure 1: Damgaard, Baltic amber inclusions - Ant (Hymenoptera, Formicidae), 2010

See these sample resin pieces (Figure 2) we have that are around 4-6 years old. Naturally, they've started to yellow, but let's discuss some of the preventive measures we take to slow down that process a bit.

Figure 2: Bupp Woodworks & Designs, 4-6 year old resin pieces, 2026

The main thing to worry about with resin is the exothermic heat that builds up while it cures, which can make it yellow prematurely. We use high-quality resin that blocks UV rays, helping to prevent that yellowing. We also pour the resin in thin layers so that too much heat doesn't get trapped. While we do have a heat gun that we use to quickly get rid of surface bubbles, our pressure chamber takes care of most of the work without adding any extra heat. Temperature and humidity also play a big role in how the resin cures and whether it stays clear. That’s why we’re very careful to control the temperature in the studio so that it's just right. 

To our customers, we recommend keeping your keepsake out of direct sunlight and consider getting a colored background, as that tends to cancel out the yellow color.

Figure 3: Bupp Woodworks & Designs, colored background resin piece, 2026

This piece here (Figure 3) is an earlier test from around six years ago made with lower-quality resin, and unless you look at it from the side, it’s pretty tough to tell that there’s any yellowing at all.