On a lighting rig, a colour is a number, not a name

Eight rectangles of colour, fanned out from one rivet at the base like a hand of cards. Cream behind them, near-black shirt around that. Every swatch carries its own number, printed small along the bottom edge — 021, 106, 132, 174, 201, 388, 715, 796.

Nobody who orders one of these says the colour out loud.

What is a gel swatch book actually for?

Choosing a colour to put in front of a lantern without holding up a show to argue about what to call it.

A sheet of coloured gel goes into a frame in front of a light and changes what colour reaches the stage, and the same number that gets picked here often ends up scrawled beside a lantern symbol on a plan long before the get-in. A swatch book is that material shrunk to sample size and bound at one edge, so a designer or an electrician can hold a whole range of colour against the same light in seconds and settle on one before the moment's gone.

Why does everyone use the number instead of the colour's name?

Because a name is somebody's opinion and a number is a thing you can order.

Ask five people what "pale amber" means and you'll get five different colours in their heads. Ask for a specific number and a wholesaler somewhere pulls the same sheet every time, because the number refers to one exact dye recipe rather than a description of how it looked to whoever named it, under whatever light they were standing in that day. The number is the part of the system that doesn't drift.

Why does the book fan from a single rivet?

Because it has to be usable in one hand.

An electrician up a ladder, or crouched by a lantern with a spanner in the other hand, needs to flick through a whole range of colour without setting anything down. A single rivet at one corner lets the whole book open like a hand fan and close again the same way, which a book bound the ordinary way, along one full edge, wouldn't do nearly as fast. Once a number's chosen it tends to stay chosen — the same figure often gets loaded straight into a preset panel set once and reused for a year.

Does a gel maker own their own numbers?

The numbering system does, and that's an entirely ordinary thing to license.

A specific manufacturer's catalogue — the exact number attached to the exact recipe they sell — belongs to the company that built the range, the same way a paint maker owns its own colour names. The numbers on this design are invented rather than lifted from a real range, which avoids that question rather than needing to answer it. Nobody, meanwhile, owns the idea of a swatch book, or the fan-from-one-rivet format itself.

Does this only mean something to a lighting electrician?

No — anyone who's had to standardise a choice that used to be a matter of opinion recognises it.

A print shop's colour-matching book runs on exactly the same logic: a name invites an argument, a number ends one. The gel book earns its place on a shirt for the same reason a matching chip does on somebody who's spent a career pinning down colour for a living — it's a badge for the unglamorous work of turning "roughly that colour" into something you can actually specify.

Isn't picking eight colours out of hundreds a strange thing to reduce to a shirt?

Not if the eight are the ones somebody actually reaches for.

A working electrician's own kit is never the full range a manufacturer sells — it's the handful of numbers that come up again and again on the shows they've actually rigged, memorised the way anyone memorises a tool used daily. Eight fanned swatches read as exactly that kind of personal shortlist, not as an attempt at the whole catalogue.

Does it print well?

Yes, and the number is the part that has to survive.

Flat, saturated colour blocks print cleanly with hard edges between them, which a fanned swatch shape gives you for free. The number stamped along each swatch needs to stay legible at a size larger than a real gel book uses — shrink it to match the genuine article and it disappears into the weave, and the whole point of the design is that the number can be read.

How do I get one made?

Describe your own range at JustOG — how many swatches, which colours, and how they should fan. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.

Designs other people have published are in the shop.

Eight numbers, no names, and every one of them orderable at four in the afternoon.