What are trial pieces and why do collectors seek them out?

On 17 November 2014, an artist at Moorcroft’s historic pottery factory picked up a squat, bulbous vase and painted a design of orange-leafed trees and flocks of red birds across a grey background.

This Birds and Trees Moorcroft vase was never meant to sit on a shop shelf. It was a trial – one version among many in the process of deciding whether it was ready for production. The handwritten ‘Trial 17-11-14’ on its base marks this piece as a working step in a design process that most people never get to see.

Trial pieces like this can be found across the collecting world, not just in Moorcroft pottery. Glassware and figurine makers also produce trial pieces to test a design before it is settled into full production, so the practice is far from unique to ceramics. So, what exactly counts as a trial piece, and why do collectors seek them out specifically?

What is a trial piece?

The artistic process is never straightforward; it requires time and patience. This is where trial pieces come in – they are pre-production experiments used to test a new design. A trial considers elements like whether the colour works against a particular glaze, if the shape suits the pattern, if the tube-lining needs to be finer or bolder, or if the right materials have been selected. All before the maker commits to full production.

A trial isn’t part of a production run, limited or numbered edition. Although there will likely be similarities to the final piece, the colour, decoration, glaze, or composition may differ.

As with the vase we described above, at Moorcroft, every design starts its life as a trial, sometimes for many years. Here’s another beautiful example: this Moorcroft pottery Ambleslade floral vase trial piece was created in 2008 and shows the characteristic tube-lined decoration, with painted and impressed factory marks on the base.

Trial pieces also often appear in glassware, not just ceramics. Timothy Harris is a leading British master glassmaker and designer who runs Isle of Wight Studio Glass. This English Bluebell glass trial vase was designed in 2003. It is signed and dated on the base and exclusive to the IOWSG Collectors Club.

There may be many trials before the artistic vision is perfected and approved as an official design. Trial pieces that show this journey prove popular with collectors.

Trial pieces: how are they different from standard production or limited editions?

It all comes down to their uniqueness.

Apart from the final trial piece (which goes into production), each design attempt is slightly different. They aren’t perfect production pieces, but they offer a real insight into the hidden stages of the design process that we rarely get to see.

Once the final design is agreed on, it is released as either an open, numbered or limited edition. Limited editions are signed by the designer and are assigned a number.

Trial pieces can get confused with seconds, artist’s proofs, prototypes or factory samples. But they do differ. A second is a quality-control reject that failed inspection. An artist’s proof is more common in printmaking and sculpture and not necessarily experimental, while prototypes or factory samples are test pieces from production trials.

Why are collectors drawn to trial or experimental pieces?

There’s something truly personal about a trial piece, which makes them a joy to collect. Even the tiniest imperfections bring character. They show a process on the way to the final flawless piece and tell a wonderful story of the creation. They also tend to be rarer than the finished editions.

Some collectors seek out trial pieces for this very reason; the colourway or finish is utterly distinctive and less commonly seen. Other collectors are hoping to complete a designer’s full body of work, while certain buyers simply prefer a trial’s aesthetic to the production piece.

The three things trial piece collectors should look for

Trials can be harder to authenticate than a numbered edition, but here are three things to keep an eye out for:

1. Marks, inscriptions or signatures: as with the examples we’ve shared above, trial pieces often carry handwritten ‘Trial’ wording, dates, designer initials, signatures or monograms alongside a factory or studio stamp.
2. Labels, boxes and paperwork: original studio boxes, documentation and dealer provenance notes (a named collection, studio archive, or event) add context and confidence.
3. Condition: with trial pieces, there is more flexibility in terms of what might be considered a ‘perfect’ production piece. But chips, cracks, restoration or heavy wear should still be checked and disclosed.

Why trial pieces aren’t always more valuable

What draws us to trial pieces is that they are honest objects. A finished limited edition tells you what the designer decided; a trial shows you their thinking process. Every mark or small imperfection in the glaze is part of that story. For collectors who care about the craft as much as the finished piece, that’s often more interesting than owning the ‘perfect’ version.

It’s important to note that just because a piece may be a one-off doesn’t mean it will attract a premium price over a standard production piece. When we provide a quotation, we consider the maker, specific design, condition, and demand.

If you’re looking to buy or sell trial ceramics or glass pieces and have questions, or are unsure about the process, our specialist team would love to help, please do contact us.