Practical Alchemy: A Potter’s Journey into The World Of Lustre Glaze

Disclaimer: This guide wasn’t written in a lab coat with latex gloves, it’s from the perspective of an inquisitive potter. Some of my thoughts, methods and processes will make you twitch if you're a chemist.

Let me clear something up straight away.

Despite what the title suggests, I’m not really a potter in the classical sense – I’m an engineer who’s wandered into the world of clay and never quite made it back out. Nicola, my partner, is the real potter here. Thirty years in the craft, instinct for form, eye for detail… all the things I lack entirely. Our approach works because we don’t trip over each other; she handles the artistic decisions, I fill my head with the technical ones, and somewhere in the middle our two approaches meet. The end result is a kind of creative truce: Nicola shapes the beauty, I build order from chaotic processes, and together we hope it turns into something worthy of firing.

Important safety notice

The processes discussed in the following sections involve hazardous chemicals and potentially dangerous procedures. Many of these substances are toxic, corrosive, volatile, or harmful to both health and the environment. They are not forgiving, and misuse can result in serious injury, long-term harm, or worse.

Nothing described here should be attempted without a full understanding of the risks involved, appropriate training, and correctly equipped facilities. Proper laboratory practice is essential, including suitable PPE, controlled ventilation, safe storage, accurate handling protocols, and emergency preparedness.

If you do not already work to recognised laboratory safety standards, do not treat this as a starting point. Your health, your eyesight, your lungs, and your long-term wellbeing may quite literally depend on it.

Where This Journey Began

Over the years I’d see plenty of folk around Tyndrum crouched over rivers and burns with pans in hand. At first it all looked a bit daft – more Klondike than Scottish Highlands. But every so often I’d stop for a chat, and some would be kind enough to show me a tiny glass vial with a few specks of gold swirling at the bottom. I’d nod, squint, and try not to look too underwhelmed.

But the more I saw it, the more it got under my skin. Nicola and I had already been talking about using locally sourced materials in our pottery – ethical, local, meaningful – and the idea started whispering: what if we could use even a little of this treasure?

Then came the early COVID days. Time slowed, wine became a sport, and Olympic-level Shiraz-training clearly had an expiry date. I needed a distraction. Like half the planet, I hit Amazon, fell down the YouTube rabbit hole, and soon had a pile of gear, a head full of half-baked knowledge, and a stubborn new mission to find shiny things in very cold rivers.

It wasn’t just a spark; it lit a fuse. I was out most days, chasing flakes that were more often than not absent. Scottish gold is notoriously rare, but that was half the appeal. Somewhere between frozen fingers and fleeting glimpses of shimmer, a bigger thought took hold: what if I could trap even the faintest trace of that gold in a glaze?

The idea didn’t fade, it grew teeth. Idle curiosity turned into full-blown obsession. I wasn’t just chasing specks in rivers anymore; I was chasing a glaze that could gleam with our very own liquid gold – a process so specialised it felt more at home in a chemistry lab than a dusty pottery shed.

The thought consumed me. Sourcing it, processing it, learning how to use our own locally gathered gold in a way that was genuinely unique, genuinely sustainable, and something very few people anywhere could honestly claim to be doing.

The Information Desert

You’d think that, in the age of the internet, someone would’ve written a clear, sane explanation of lustre glaze chemistry. A recipe even.

Not even close.

There are endless discussions on applying lustre. Mountains of china-painting advice. But the actual chemistry – the why, the how, and the reason it either shines beautifully or fails dramatically – was maddeningly elusive. That frustration is what pushed me to start documenting everything. Partly so I’d remember what I’d done, partly so the next poor soul might save themselves a few years and a bit of heartache.

Having exhausted Google, I went old school and started collecting books. Every title that so much as whispered “lustre glaze” got added to my shelf, quickly forming a small but absurdly expensive library of disappointment. In the end only three proved genuinely useful:

Pottery Decorating — Hainbach
Industrial Ceramics (Volume 2) — Singer & Singer
Lustre — Greg Daly

Between them I finally had enough technical hints to attempt real experiments.

The Trouble with Tradition

Traditional lustre recipes have charm, but they’re feral.

Many are chemically unstable and need to be mixed fresh every time. Others produce dull, patchy results, or rely on relentless burnishing just to coax out a half-decent shine. Most stink to high heaven, and nearly all are written in that vague Victorian recipe-book style with no accurate ingredients, no precise weights, and plenty of guesswork.

I came across several different recipes, but they all followed a broadly similar pattern: take a natural resin or oil, boil it with sulphur, bismuth and a salt of gold, sometimes with small additions of other metals like rhodium, copper or antimony. Thin the mixture with turps, eucalyptus or rosemary oil (or more often than not a cocktail of several natural volatile oils), let the solids settle, then skim off the clearer upper layer and hope for the best.

I loved the spirit of those old formulas, but they felt imprecise and wasteful. They were unstable and had painfully short shelf lives. Still, I pushed on, and with each attempt the results improved. Given enough time and experimentation, I’ve no doubt I could have produced something genuinely usable. But it began to feel like energy better spent looking forward, not backwards.

Which led to the far more interesting question:

Why do modern bright gold lustres work so well?

The commercial versions are flawless – mirror-like, consistent, stable, reliable. Practically magic. So what’s in them? What makes them tick?

That’s where this phase of the journey really begins: digging into the science behind modern bright gold lustres. I’ll use gold as the main example, but much of what follows can be applied to other metals too, each unlocking its own colours and effects.

Although I drew on a wide range of sources to understand the chemistry behind how this all works, I refused to simply copy other people’s formulas. I’m an engineer. I wanted to understand why these processes were used, to fill in the many missing details, and to approach it from the perspective of an end user rather than a manufacturer. I wasn’t interested in recreating what already existed - I wanted to improve it.

And I did. I identified and solved a glaring weakness in many modern gold lustre formulas: on certain glazes, commercial lustres are incredibly difficult to see during application. A small issue on paper, but a significant one in practice. Read on and you’ll see how I overcame this and introduced a creative solution that, as far as I can tell, the big manufacturers haven’t come close to addressing.

What You’ll Learn

The essential components of a bright gold lustre glaze and what each one contributes
The challenges of traditional recipes versus modern formulations
How solvents and resins influence application and firing
The role of fluxes, micro-additives, and other helpers in achieving that perfect shine
Practical insights from months of trial, error, swearing, and eventual success

The Chemical Symphony

A resinate gold lustre glaze, to give it its Sunday name, is built from just a few core components. Each brings its own behaviour, and the final result depends entirely on balance. Think of it as a chemical symphony: every part has to enter on cue. A single misstep – a misbehaving solvent, the wrong ratio, an uneven film – and the whole performance falls apart.

Instead of a brilliant, even layer of gold, you’re left with streaks, black spots, dull patches, or a complete failure to bond.

My main nemesis in the early days was trying to wrangle all these players at once. Was there too much resin? Too little bismuth? And what exactly was that suspicious goo lurking at the bottom of the vial? Something unimportant… or something vital that had quietly dropped out of the mix?

Here are the players in that symphony:

The Vehicle

The resin matrix. Holds everything together once the solvent evaporates. Needs to burn away cleanly, stay stable, and behave predictably. Think scaffolding that bows out just before the curtain rises. Historically these were made from pine resin, linseed oil, and thickened turpentine.

The Recipe

Now that you know the orchestra, it’s time to look at the symphony itself, the recipe and how all these parts fit together to make a usable lustre glaze.