Personal journey and practical motivation behind learning gold lustre chemistry

LET ME CLEAR SOMETHING UP

Despite what the title suggests, I’m not really a potter, at least not in the classical sense. I’m an engineer who wandered into the world of clay and never quite found the exit.

Nicola, my partner, is the potter. Thirty years in the craft, an instinct for form, an eye for detail, everything I entirely lack. Together we run Tyndrum Pottery, a small studio in the Scottish Highlands, with a stunning backdrop that inevitably finds its way into our work.

We’ve always tried to keep what we make grounded in where and how we live. That means using ethically sourced materials, paying attention to provenance, and working in a way that doesn’t feel at odds with the landscape around us. If something goes into the pot, we want to know where it came from, how it was extracted, and whether it is sustainable.

That way of thinking is what led directly to this guide. Gold mining, as it’s practiced in much of the world, is highly destructive: polluted waterways, exploited labour, and supply chains most people would rather not look too closely at. Working with gold without confronting that reality never sat comfortably with us.

Our division of labour works. Nicola makes the artistic decisions, I obsess over the technical ones, and somewhere in the overlap a truce is formed. She shapes the work, I wrestle with the processes behind it, and this guide lives firmly in my half of that overlap.

WHERE MY JOURNEY BEGAN

Around our home in Tyndrum you’ll often see people crouched over rivers and burns, shaking pans like they’re auditioning for a Highland remake of the Klondike. I used to think it was a bit daft, standing knee-deep in a freezing burn for hours at a time in the hope of catching a flake or two. Occasionally I’d stop for a chat. Some would be kind enough to show me a tiny glass vial with a few shimmering specks of gold swirling at the bottom. I’d squint, nod politely, and try not to look too underwhelmed.

But the idea stuck.

Tyndrum sits on a major geological fault rich in minerals, and people have been pulling tiny traces of gold from its rivers for generations. Nicola and I were already exploring ways to use locally sourced materials in our pottery. Ethical. Local. Meaningful. And the thought kept nagging away: what if we could use even a little of this in our work?

Then came the early COVID days. Time slowed. Wine consumption accelerated. Olympic-level Shiraz training clearly wasn't sustainable. I needed a distraction.

Like half the planet, I fell down the Amazon and YouTube rabbit hole and emerged with a pile of gear, a head full of half-baked knowledge, and a stubborn desire to find shiny things in very cold rivers.

Somewhere between numb fingers and fleeting glints, the idea grew. I didn’t just want to find gold. I wanted to use it. To fold even the smallest trace of local gold into our very own lustre glaze.

Once that thought landed, it didn’t let go.

THE INFORMATION DESERT

You’d think that in the age of the internet someone, somewhere, would have written a clear explanation of lustre chemistry, a sensible breakdown? a structured recipe? anything? Nope.

There’s plenty of advice on how to apply lustre, endless discussion in China-painting circles, but the actual chemistry, the why and how, is elusive to the point of absence.

That frustration is what pushed me to start documenting everything. Partly for myself. Partly for the next poor sod who tries this and would rather not waste two years and more money than I'm comfortable admitting.

After squeezing the internet dry, I turned to books. Any title that whispered “lustre” ended up on my shelf, forming a small but impressively expensive library of disappointment.

In the end, only three were genuinely useful:

• Hainbach, Rudolf. Pottery Decorating (A Description of All the Processes for Decorating Pottery and Porcelain. Scott, Greenwood & Sons, 1907. (Much of the glaze and decoration chemistry found in 19th/early 20th-century studio practice was recorded here)

• Singer & Singer. Industrial Ceramics, Volume 2. (Specific publication details vary by edition; this is conventionally cited as part of a multi-volume reference series on ceramic materials and processes.)

• Daly, Greg. Lustre. Ceramics Handbooks series, Bloomsbury Publishing PLC, 2018. (A contemporary potter’s handbook covering lustre techniques and formulations)

Between them, I finally had enough fragments to begin proper experiments.

THE TROUBLE WITH TRADITION

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

Many are chemically unstable and must be mixed fresh every time. Others give patchy, dull results or demand relentless burnishing just to coax out a shine. Most smell like they were designed by someone with a grudge against noses. Nearly all are written in a vague Victorian style: imprecise ingredients, no weights, endless guesswork.

Most follow the same pattern. Take a resin or oil, boil it with sulphur, bismuth, and gold chloride, thin it with turpentine, eucalyptus/rosemary oil and hope it behaves.

I loved the spirit of those recipes, and I pushed on regardless. Results improved slowly, but it eventually became clear that my energy was better spent looking forward, not backward.

So why do modern bright gold lustres work?

Commercial bright gold is flawless. Mirror-like. Consistent. Stable. Practically magic.

Which raises the obvious questions:

What’s actually in them? And why do they work so well?

Those questions are the real starting point of this guide.

In trying to answer these questions, I found myself wading into a strange halfway world of safety data sheets, old patents, and carefully worded technical documents.

It was a steep learning curve. Deciphering SDS disclosures, cross-referencing any and all patents I could lay hands on, and slowly realising that the most important information is often what isn’t stated outright. Buried in those documents were the breadcrumbs that mattered: which types of gold compounds were being used, how binders behaved, why certain solvents kept reappearing, and why trace additions showed up again and again.

I wasn’t interested in copying formulas or guarded recipes. I wanted to understand what each component was doing and why it was there, and to approach lustre as a potter who actually uses the material and lives with its behaviour.

Over time, modern bright gold lustre stopped looking like black magic and started to resemble what it really is: a finely tuned chemical recipe.

ONE PRACTICAL PROBLEM NO ONE TALKS ABOUT

Somewhere along the way I ran into a problem that almost never gets mentioned, but drives me quietly mad: on certain glazes, lustres are nearly impossible to see while you’re applying them.

With older, resin-heavy lustres you could at least see something. Modern systems are a different beast. Many of the ingredients are almost colourless and translucent, which is great chemically, but awful when you’re trying to judge where you’ve been, how thick the film is, or whether you’ve missed a patch entirely.

On paper it sounds trivial. In practice it’s a genuine headache, especially on dark, glossy glazes where it simply disappears under the brush.

I eventually found a simple, elegant way around this. As far as I can tell, it’s something the big manufacturers either ignored or implemented with a crude dye.

Read on, and you’ll see exactly how it fits into my system.

WHAT YOU'LL LEARN

• The essential components of a bright gold lustre system

• Why historical and modern formulations behave so differently

• How solvents, binders, and fluxes shape application and firing

• Why micro-additives matter far more than their quantities suggest

• Practical lessons learned through months of trial, error, and swearing

A SIMPLE MENTAL SHIFT

This is the one idea I want to land before we go any further. Once it’s properly lodged, the rest of the guide starts to make more sense.

In a lustre glaze, everything you add must be fully soluble. Not suspended. Not “mostly mixed.” Properly dissolved. And once dissolved, those components must coexist without reacting with each other. They need to sit there, quietly, doing nothing, right up until they are brushed on a piece.

That’s the entire game.

Throughout this guide you’ll see familiar chemicals being pushed into unfamiliar territory. That isn’t an optional step, it’s necessity. The aim is almost always the same: take something you already know and turn it into a new, soluble cousin that can survive in this system without causing trouble.

I find it helps to think of the lustre as an orchestra. Every component is already in place before the piece goes into the kiln. The solvent, the binder, the gold, the flux, the small additions, each has a role to play. The kiln is the conductor. As the temperature rises, each part is meant to come in and bow out at exactly the right moment.

Choose the wrong solvent, something drops out early, pick a binder that softens too soon, and the film starts to migrate. Let one component react before it’s meant to, and the whole performance collapses. Instead of a clean metallic finish, you’re left with black specks, migrating films, or no shine at all.

Once you start thinking about lustres this way, the chemistry stops looking like black magic and looks more like a system.