Why does cobalt always turn glazes blue?

1the atom

It's not magic — it's about electrons in the cobalt atom absorbing certain colors of light and letting blue bounce back to your eye.

2white light in

White light hits the glaze carrying every color. Cobalt's electrons soak up the red, orange and yellow wavelengths.

3absorbed

Those absorbed colors get trapped as the electrons jump energy levels — that jump exactly matches red-orange-yellow light energy.

4blue reflects

Blue light isn't absorbed — it reflects straight back out to your eye, so that's the only color left for you to see.

5other metals

Different metals have differently-spaced electron levels — that's why iron often makes green or brown, and copper makes turquoise, not blue.