Color Matching& Artwork Standards

The same colour code passes through three completely different physical systems before it reaches a finished pin, and each one changes the result in its own way.

A screen emits light; enamel reflects it. A screen has a fixed white point and a fixed gamma; the room around you does not. And between the screen and the finished part sits a metal body whose own colour is part of the result: the same enamel over brass, over zinc alloy and over aluminium is not the same enamel, and a light or pastel mix will show the substrate far more than a dark one does.

This is not a supplier failing to try hard enough. It is a mismatch between two media, and no amount of care closes it. What care can do is move the agreement onto something that does not depend on either medium — which is where the Pantone code comes in.

Most colour disputes are not colour disputes. They are file disputes that surface later, when a line is too thin to hold enamel or a font has quietly changed shape on someone else's machine. A production-ready file is not a beautiful file; it is a file with no remaining decisions in it.

• 01

  Vector, 1:1, with real dimensions

  A file drawn at 1:1 removes one class of error before it starts. Scaled artwork invites scaled line weights, and a 0.2 mm line that becomes 0.15 mm after scaling is no longer a line the process can hold.

• 02

  One closed path per colour

  Every colour area is a closed shape, separate from its neighbours. The metal between them is not a stroke you draw — it is the space the die leaves behind, so the gap has to exist in the geometry.

• 03

  A Pantone code on every area

  Not a hex value, not an RGB triplet, not “the blue from the website”. Each shape carries a Pantone code, and the count of codes is the colour count that gets quoted.

• 04

  Text outlined, not live

  Fonts get substituted, weights get lost, and a re-flowed line changes the metal around it. Convert type to outlines, then check the smallest stroke against the process minimum.

• 05

  No gradients, halftones, shadows or transparency

  Enamel is a solid colour in a cell. Anything that depends on a smooth transition has to become print, a dome, or a different design — and that decision belongs before the tool is cut, not after.

• 06

  Front and back registered to one origin

  Double-sided parts are checked against each other. If both faces are drawn from the same centre line and the same trim, alignment is a measurement; if they are drawn separately, it is a hope.

In a metal workshop, colour is not matched to a file. It is matched to a Pantone code, and that code is the reference the whole shop organises around: the mixing bench, the sample room, the inspection bench, and the reorder two years later all read from the same number.

The code is a reference, not a recipe, and being honest about that is what makes it usable. A Pantone chip is ink on coated paper. Enamel is pigment in a binder over metal. They can be brought close, and a good mixing bench brings them very close — but the code fixes the intention, while the substrate, the enamel thickness and the finish decide the result.

Three practical consequences follow. Codes in the metallic range cannot be reproduced as flat enamel at all — they need a metallic base or a plated field, and a proof should say so rather than quietly substituting. Pastel and light mixes sit closer to the substrate and shift more than dark ones. And a chip that has been sitting in a window for a year is no longer a reference, which is why the book gets replaced rather than trusted indefinitely.

This is the step that decides whether the finished part is right, and it happens before any metal is cut. The proof we send back is not a picture of the design. It is the design with every colour area numbered and its Pantone code listed beside it, plus the colour count, the substrate and the plating. The client confirms the codes — not the impression — and production starts after that confirmation.

• 01

  PANTONE 186 C

  FieldFlat enamel. Reproducible as drawn.

• 02

  PANTONE 872 C

  AccentMetallic. Needs a metallic base — flat enamel will read duller.

• 03

  Bare metal

  BorderNo enamel at all. This is the plating colour, not an ink.

• 04

  PANTONE 423 C

  BackgroundDark field. Substrate shows through less, so it holds closer.

Why this step removes the error the client is actually worried about: once the agreement is a list of codes, there is nothing left for a monitor, a phone photo or a tired pair of eyes to disagree with. Two people in two countries can read the same proof and be confirming the same thing. The conversation moves from “does it look right” to “is 186 C the red you mean”, and the second question has an answer.

ΔE is the distance between two colours in a colour space. It is a genuinely useful number, and it is also the most misused one in this trade — because a ΔE value on its own does not describe anything. It describes a difference under a set of conditions, and if the conditions are not stated, the number cannot be reproduced or argued with.

Two formulas are in common use. ΔE*ab from 1976 is a straight Euclidean distance; ΔE00 from 2000 corrects for the fact that the eye is more sensitive to some directions in colour space than others. For the same pair of samples, ΔE00 usually returns a smaller number than ΔE*ab — so “≤ 1.5” means two different things depending on which one is being quoted, and neither is meaningful without the rest of the conditions.

• The formula — ΔE*ab (1976) or ΔE00 (2000). The same number is not the same difference.
• The illuminant — D65 is the reference; tungsten or a phone torch will answer differently.
• The observer — 10° standard observer, not 2°.
• The geometry — 45/0 or an integrating sphere, with specular included or excluded.
• The spot — a flat enamel field, away from metal lines, edges and curvature.

This is why we do not publish a single ΔE threshold as the definition of a correct colour. What we stand behind is narrower and more useful: the Pantone code on the signed proof, on the stated substrate, matched by the recorded formula, with a cured sample kept as the reference. ΔE is used to check drift between batches and to settle a disagreement with a number instead of an opinion — not to replace the reference that was agreed.

Four situations come up often enough to name. None of them means the measurement is wrong or the eye is wrong; they mean the two are answering slightly different questions.

The practical response to all four is the same: judge colour under the light the part will actually be seen in, on the actual substrate, at the actual size. A colour that only matches on a 50 mm patch under a lab lamp has not been approved for a 3 mm line on a pin.

The whole system only works if the handover is complete. These are the two lists worth checking before a project starts — the first on your side, the second on ours.

If a supplier starts production before you have confirmed the codes in writing, the colour conversation has already been lost — whatever happens afterwards is a discussion about who remembers what, and memory is not a reference.