Historical lustres and what's different in modern formulations

A resinate lustre is a thin-film chemical system designed to sit on top of an already fired glaze. It’s applied as a liquid, allowed to dry, then taken through a separate, lower-temperature firing. During that firing the organic components burn away, the surface of the glaze beneath softens slightly, and a microscopic metallic layer becomes bonded into that surface.

Most potters already know lustres aren’t just another glaze. Where the confusion usually creeps in is where the important chemistry actually happens.

In a lustre system, the kiln doesn’t create order from chaos. It executes what you’ve already set up. If the chemistry isn’t behaving while everything is still liquid, the firing won’t fix it. It will simply make the poor outcome permanent.

WHERE THE REAL WORK HAPPENS

By the time a lustre goes anywhere near heat, every component already needs to be in the right chemical form. Metals, resins, fluxes, and additives must dissolve, coexist, and form a stable, even film on the surface of the pot. That film then has to survive drying without cracking, crawling, or flaking before it ever sees the kiln.

During firing, solvents burn off, resins soften and decompose, and metal compounds break down. What remains is locked into the glaze surface below. The kiln’s role is critical, but it’s not forgiving. It doesn’t make incompatible ingredients behave, it only reveals whether they ever did.

This is why solubility sits at the heart of lustre chemistry.

A SHORT HISTORY OF LUSTRE

How this was done before we understood what was going on

Lustre isn’t a modern invention. It first appeared in the Islamic world around the 9th century, where potters discovered that metals such as gold, copper and silver could be coaxed into forming thin metallic films on glazed surfaces at relatively low temperatures. They didn’t have the language of chemistry, but they had careful observation, repetition, and a strong incentive to make beautiful things without using solid gold.

Those early lustres were made using what we’d now recognise as crude resinate systems. Metal salts were combined with organic materials such as plant resins, oils, and sulphur-rich compounds, painted onto glazed wares, and fired in reduction. The organics burned away, and the metals were left behind as shimmering surface films.

The process worked, but it was unpredictable. Recipes were closely guarded,  undocumented, and heavily dependent on local materials and kiln conditions. Results varied widely, even when following the same method.

In the 19th century, lustre saw a major revival, particularly in Europe. Victorian makers didn’t just rediscover the technique, they industrialised it. Thick, resin-heavy mixtures based on pine resin, turpentine, sulphur, and metal salts became common, and in skilled hands they produced extraordinary results. Some of these lustres achieved levels of richness, depth, and durability that are still admired today, and many remain in continuous production.

These systems weren’t crude or careless. They represented the practical limits of the materials available at the time.

Those resin–sulphur systems worked by bundling multiple roles into the same ingredients. The resin acted simultaneously as binder, film former, and active component. Sulphur participated in converting metal salts into more organophilic, soluble forms rather than true solutions. Oils and turpentines adjusted flow and drying. Each material performed several functions at once, largely out of necessity rather than design.

That complexity made the systems sensitive. Shelf life was often short, batches had to be mixed fresh, and small changes in materials or handling could push them off balance. Burnishing wasn’t just aesthetic, it was often the only way of forcing a shine after firing rather than guaranteeing it chemically.

What all of these systems shared was the same underlying idea: dissolve metals into an organic medium, apply them thinly, then let heat strip everything away except the metal.

What changed over time wasn’t the goal.
It was control.

Somewhere along the way, certain recipes began to stand out. They were described as bright liquid gold or self-burnishing gold, and for once the descriptions were accurate. These formulations behaved better, fired cleaner, and produced a brighter, more reliable metallic film.

The common thread, once you start digging, is the quiet introduction of trace metals like copper, rhodium, antimony and tin. Tiny additions, barely there in the recipes, but with an outsized effect on how the whole system behaved.

At the time, I didn’t fully understand what they were doing. I assumed they were alloying with the gold, making the gold a bit shinier. I wasn’t entirely wrong, but the reality turned out to be more subtle, and it’s something I dig into properly in the micro-additions section.

WHY SOLUBILITY MATTERS SO MUCH

Modern lustre systems aim to remove as much uncertainty as possible by separating roles that were once bundled together. Instead of relying on sulphurised resins to both dissolve metals and form films, metals can be prepared in purpose-built organometalic forms. Instead of hoping a resin behaves well during drying and burnout, theres a huge selection of polymers that can be chosen for known thermal properties. Instead of natural oils, modern solvents can be employed for precision evaporation curves.

In a fired lustre, the metallic layer is only a few atoms thick. At that scale, everything needs to mix at the molecular level. An undissolved oxide particle, even ground as fine as you like, is effectively a boulder dropped onto a salt flat. You can suspend it, smear it around, and convince yourself it’s well mixed, but it never truly becomes part of the system. When things go wrong later, that’s often where the trouble started, something quietly fell out of its soluble state pre-application.

This is why materials that behave perfectly well in conventional ceramic glazes can be completely wrong for lustres. The entire approach laid out in this guide grows from that realisation: your taking familiar sounding materials and deliberately pushing them into forms that are fully soluble, shelf-stable, and able to coexist without quietly reacting or falling out of the solution.

WHAT THE FIRING ACTUALLY DOES

When the piece goes into the kiln, the firing still matters. Solvents burn off. Resins soften and decompose. Metal compounds break down and, with the help of fluxes, a thin metallic layer is bonded into the glaze surface beneath.

If everything was balanced properly beforehand, this happens cleanly. If it wasn’t, the firing makes that painfully obvious. Lustres are unforgiving not because they’re temperamental or mystical, but because you’re working with chemically active materials from the start.

The mental shift that finally made lustres make sense for me was simple: you’re not making something to melt. You’re making something that has to behave while liquid, then decompose on cue, cleanly under heat.