The Story of the First Caustic Feature on a UK Coin

At the Council of Elrond in The Lord of the Rings: The Fellowship of the Ring, Boromir describes the barren and unforgiving landscape of Mordor, decrying “There is evil there that does not sleep, and the Great Eye is ever watchful.” He refers to the Eye of Sauron, which features in the film franchise only a handful of times, as a gigantic eye wreathed in flame, perched above the formidable stronghold of Barad-dûr.

It’s no surprise, then, that such a menacing yet iconic motif serves as the first caustic feature we have struck on a UK coin.

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What are Caustics?

Caustics has been around for some time, initially investigated mathematically for rendering photo-realistic virtual images of digital models. Later, ‘caustic engineering’ was developed as a method of developing physical objects in reflective materials to focus light to create a desired image onto a target surface.

An example of caustics at play is when light shines on a drinking glass. The glass casts a shadow but also produces a curved area of bright light. This effect can be manipulated to create a distinct pattern, which is exactly what we did for the first coin in our collection celebrating The Lord of the Rings film trilogy.

The Eye of Sauron Glowers on a Coin

With more than 20 years’ experience working at The Royal Mint, as well as several coin designs to his name, Thomas T. Docherty is the product designer responsible for finessing and producing the first caustic feature we have applied to a UK coin.

The designer chose to feature a graphic representation of the Eye of Sauron as the central asset for the coin design. Serving as the focal point and hero element of the overall composition, its symbolic significance made it ideally suited to occupy the negative space at the centre of the ring in the design.

We caught up with him for a fascinating insight into how the caustic was engineered, as well as the composition of his coin design – the beauty of which would seduce and enthral Sauron himself!

Prologue

“When the project came in, there was the immediate idea to look at using a caustic device and how we could incorporate it into the overarching design, while also ensuring it wasn’t just a stand-alone element.”

“Then there was the idea of using the ring – being such a key part of the story – which would give us a really good opportunity to use a large negative space within which the caustic could be positioned.”

Riddles in the Dark

The final line inscribed on the One Ring translates to ‘One Ring to bring them all and in the darkness bind them’. In the context of creating a caustic feature on a UK coin for the first time, which was a challenging feat, darkness was the product designer’s ally when it came to testing and development.

“I did a lot of testing, which was digital at first to test the caustic at size. This involves essentially staging a light environment, so you never know for certain if the digital render will work until you experiment with a physical coin. Fortunately, in this case, the physical experimentation produced a better result than the digital renders.

“The relief used to create the caustic effect on this coin is extremely subtle. It’s ideally suited to line art rather than a rendered tonal image. I created curves of relief that reflect light onto a point; that point then mirrors the fine line of the pattern onto a surface.”

The Great Eye

Lidless and unblinking, the Eye of Sauron is as iconic as it is terrifying. However, The Lord of the Rings film trilogy is replete with iconic imagery and symbols, each of which could have served as a fitting caustic feature.

“I began experimenting with different imagery to serve as the caustic device; this included the Tree of Gondor and Arwen’s Evenstar pendant, as well as the Elvish symbol for ‘25’ to give a nod to the franchise’s anniversary.

“Then we started to consider the Eye of Sauron and theorise how that would that work, using renders to model how the caustic effect would function on a practical level. This involved finessing the image and altering focal lengths, making the Eye crisper and clearer on the inside but more blurred on the outside to create a feathered edge, which in turn creates the flaming effect that is so powerful and striking in the films.

“Overall, using the Eye of Sauron as a caustic device worked out perfect as caustics are all about light play, so being able to replicate the flames from the Eye was ideal.”

‘One Ring to Rule Them All’

In addition to the Eye of Sauron serving as the caustic feature, the reverse design pays tribute to the One Ring. In the films, despite being “such a little thing”, as Boromir refers to it, Middle-earth’s fate hinges on its destruction. It was therefore essential for the One Ring and its iconic inscription to feature at the forefront of the design.

“The ring is such a key part of the story and is instantly recognisable – people will know exactly what the coin is celebrating when they see it. Choosing the One Ring also gave us a good opportunity to use a large negative space in which the caustic feature could sit, so there was a technical element to choosing it as well as thematic.

“The positioning of the Elvish text was also a consideration. It’s heavily italicised and I wanted to create a sense of movement and dynamism to the design, so I created this radial composition that makes the text seem as if it’s spinning out from the centre of the design.

“Ultimately, it all comes back to being a balancing act of ensuring the ring is portrayed at an effective size for legibility so people can recognise it, the caustic fits and works from a technical viewpoint, and the elvish text works in tandem with the other elements to bring the whole design together.”