Will clear epoxy amber over a white countertop or light-colored surface?

It can. With any epoxy, there are only two situations where yellowing occurs: outdoors under UV exposure, and when clear epoxy is applied over a white background such as a white granite countertop.

We developed UltraClear Art & Craft Epoxy specifically to solve the clear-resin-over-white problem. It is made with HALS UV stabilization, offers the highest level of UV resistance of any of our products, and works perfectly over white, pastel and light-colored backgrounds. One thing to keep in mind for a white kitchen counter or other high-use surface: Art & Craft Epoxy is less durable than UltraClear Bar & Table Top Epoxy, which is the better choice for high-use surfaces, so weigh that against the yellowing risk when choosing.

The same applies to artwork. Art & Craft Epoxy is what we recommend over paintings, and for outdoor pieces with white or light areas, such as a mural, it is the best option as long as you can pour it flat and level like a standard table top pour. Outdoors, remember that UV exposure will eventually yellow any resin; the UV inhibitors extend the lifespan, and a UV polyurethane topcoat over the cured epoxy extends it further.

UltraClear Art & Craft Epoxy: https://www.bestbartopepoxy.com/products/art-and-craft-epoxy