Guides / Finishing

Colour Matching a Keyboard Case Across a Run

September 21, 2026

Colour is where keyboard runs go wrong. Not machining, which is predictable and measurable, but colour, which is judged by a few hundred people holding a part under their own lighting and comparing it to a render they saw eight months earlier.

The technical reasons colour moves are covered in how anodised colour is really decided. This is the operational half: what you actually do about it.

Stop using renders as a colour target

A render is emitted light on a calibrated screen. An anodised case is reflected light off a textured surface. They cannot agree, and every attempt to make them agree ends with a shop being blamed for physics.

Marketing renders are fine. Use them to sell the board. Just never send one to a shop as the colour target, and try to keep the gap between the render and the achievable colour small enough that your buyers are not surprised.

Use a reference number, then a physical sample

Start with a Pantone or RAL number. It gives the shop a defined starting point, it is unambiguous in an email, and it survives translation.

Then get a physical sample made and approve it in your hands. The reference number gets the anodiser into the right neighbourhood; the sample is the actual target. On an anodised part the number alone will never be enough, because the alloy and the blast grit both shift the result.

If you already have a part in the colour you want, from an earlier run or another product, send that. It is the best colour brief there is.

The golden sample

When you approve a sample, that physical object becomes the standard for the run.

Make it explicit. Both parties should have a copy where possible, and the agreement should say plainly that the approved sample is the acceptance standard rather than the drawing note or the reference number.

Keep yours in a drawer, unscratched and out of sunlight. It is evidence, and in month five when someone says a batch looks light, it is the only evidence either side has.

Batching is the whole game

Dye depletes as parts are processed. Bath temperature drifts through a shift. Time in the dye is judged by an operator.

None of that can be specified away. It can only be contained, and it is contained by putting every part that has to match into the same load.

Write it on the purchase order in plain words: top case, bottom case and any exterior part to be anodised in the same batch. This costs nothing and it prevents the single most visible failure this process has, which is two halves of one board being subtly different along a seam that runs the full perimeter.

What happens when a batch misses

Decide this before it happens, because it sometimes will.

There are three reasonable outcomes and they should be named in the agreement:

Strip and redo. Anodising can be stripped and the part reprocessed. It removes material and it does not always come back the same, so it is not unlimited, but it is usually the first option.

Accept with a discount. If the miss is small and you would rather ship on time, this is a legitimate commercial answer. Say so early rather than after an argument.

Remake from raw. Expensive and slow, and the correct answer when the miss is large.

The conversation you want to avoid is the one where nobody agreed what “acceptable” meant. That belongs in a written cosmetic standard.

Repeat colourways

A year later you want the same blue again. Treat it as a new colour.

The original dye lot is gone. The bath is different. The operator may be different. The shop may have changed anodisers. Ask up front whether a repeat is realistic, get a new sample approved with the original golden sample in your hand for comparison, and if there is a visible difference, tell your buyers before they pay rather than after they unbox.

People are remarkably forgiving about an honest “round two is a shade lighter, here is a photo of both”. They are not forgiving about discovering it themselves.

A short operating procedure

1. Pick a reference number for the brief.
2. Get a physical sample made in the production alloy, blast and process.
3. Approve it in daylight and under lamp light.
4. Name it the golden sample in writing, keep a copy each.
5. Require matching parts to share an anodising load, on the purchase order.
6. Agree in advance what happens if a batch misses.
7. Inspect the first production batch against the sample, not the render.

Seven steps, most of them free. They turn colour from the biggest risk in the project into a managed one.

Frequently asked questions

Keep reading

• Two Colours on One Case: What Masking Adds to an Anodised Run
• Specifying E-White So Cases Match Each Other and the Keycaps