Why Your Cup Colour Doesn't Match the Pantone Chip — and How to Approve It Properly

Quick Answer

A Pantone number describes ink printed on paper. Your cup is pigment dispersed in plastic, moulded into a shape, with a surface texture and a gloss level. The chip and the cup are two different materials doing two different things with the same reference — so a small difference is normal, not a mistake.

What you can control is the size of the difference and whether it repeats. Approve a physical master sample (not a screen preview), check it under the light your customer will actually use, write a tolerance into the order, and keep a signed reference piece on both sides. Do those four things and colour stops being a recurring argument.

Below: where the difference comes from, what ΔE numbers mean in practice, which colour system to specify, the seven production variables that shift colour without anyone changing the formula, and a triage procedure for a batch that arrives wrong.

Where Does the Difference Come From?

One number passes through four rendering stages before it reaches your customer. Each stage can move it.

Why Does the Same Number Look Different on Plastic and on Paper?

Four physical reasons, in order of how much they matter:

• Surface gloss. A gloss surface reflects a hard highlight and reads darker and more saturated; a matte surface scatters light and reads lighter and flatter. Same pigment, visibly different cup.
• Opacity. Paper is opaque. Plastic can be opaque, translucent or clear. A translucent colour shows the wall behind it, so the cup reads darker where the wall is thick and lighter at the rim.
• Texture. A moulded texture (sandblast, leather grain, fine matte) changes how light leaves the surface. Moving from smooth to textured on the same colour will read as a half-step lighter, sometimes more.
• Material. PP, ABS, PET, Tritan and silicone each render pigment slightly differently. A colour approved on an ABS lid will not automatically match on a PP body.

There is also a formal name for the lighting problem: metamerism. Two colours can match under daylight and diverge under warm shop lighting or under LED. If your product is sold in a retail environment with a specific light, the approval has to happen under that light — or at least be checked under it before you sign.

Should You Specify Pantone, RAL or a Physical Sample?

Use all three, in this order of authority. Most colour disputes start with a buyer sending only a number.

The strongest brief is a number plus a physical sample plus a sentence about the surface: “match this Pantone to this sample, on a matte textured body, gloss level 5–8, opaque.” That sentence removes three of the four variables before the first sample is made.

What Does ΔE Actually Tell You?

ΔE is a single number for the distance between two colours in a standard colour space. It turns a subjective argument into a measurement — with one caveat: ΔE is only comparable when both readings come from the same instrument type and the same measurement geometry. A supplier quoting ΔE from a different device is quoting a different ruler.

Two practical rules. First, agree the tolerance before the sample is made, not after it arrives. Second, never accept a ΔE figure alone — ask for it together with a photograph and a physical sample, because ΔE cannot see a patchy surface, a flow line or a colour that is even but wrong.

How Should You Approve a Colour So It Sticks?

What If You Cannot Post a Physical Sample?

Send the number, then ask the factory to courier three moulded chips in the intended material and finish, and keep one of them as the reference. A photo of a chip on a white desk is not a reference: the camera white balance, the screen and the room light each move the colour more than the tolerance you are arguing about.

If the product must match something you already own — an existing cup, a printed carton, a brand guideline printed on paper — send that object, not its description. Matching to a physical article is faster and cheaper than matching to a number that has already been interpreted once.

This is the part that decides whether your second order matches your first. Seven steps, and the whole thing takes about a week.

1. Send a reference, not a screenshot. A number, a physical sample, or both. Screens render colour unpredictably and are not a reference.
2. Say where it will be seen. Retail shelf under warm light, outdoor event in daylight, or a photo studio. This decides the illuminant you approve under.
3. Get a physical master sample. Not a colour card, not a digital mockup — a moulded part in the intended material, texture and gloss.
4. Check it under at least two light sources. Daylight (D65, roughly 6500K) first, then the light your customer will actually use — warm indoor, or cool LED retail. If it holds in both, it is a robust match.
5. Sign and date the sample. Three pieces: one retained by the buyer, one by the factory, one sealed and stored. The sealed one is what settles a dispute a year later.
6. Write the tolerance into the order. One line: the approved reference, the ΔE limit, the light source used for approval, and “no change to pigment, material or texture without written approval”.
7. Photograph the approved piece in fixed conditions. A photo is not the reference, but it catches gross errors on incoming batches faster than anything else.

Which Colour System Should You Use — Masterbatch, Pre-compound or Dry Blend?

The same colour can be delivered three ways, with very different consistency. This is the single most under-specified item in colour briefs.

Ask which one you are being quoted. A price difference between two suppliers on the same colour is often this, and nothing else. If the answer is masterbatch, ask for the let-down ratio in writing — a ratio that drifts from 2% to 2.2% is a visible colour change on light shades.

What Shifts Colour Without Anyone Touching the Formula?

Seven production variables. All of them are normal process variation, none of them require a new colour, and every one of them has produced an angry email.

There is an eighth that is not a variable at all: a different mould. If your supplier runs the same colour in a second cavity set or a second machine, expect a small difference. For a multi-part product, insist that body and lid come off the same colour lot — mixing lots is exactly how a two-tone set happens by accident.

How Do You Stop Colour Drifting on Repeat Orders?

• Keep the sealed reference. Not a chip, not a photo — the physical approved piece, stored away from light and heat. Plastic yellows and ink fades, so replace the working reference every 12–18 months against the sealed one.
• Fix the recipe to a single compounder. Two suppliers matching the same Pantone number will produce two different plastics. Colour is a supply-chain commitment, not a specification.
• Order colour in one lot where possible. A single 500 kg pre-compound lot covers a large order and removes lot-to-lot drift entirely.
• Re-approve after any material change. Recycled content, a new resin grade or a formulation update from the compounder all reset the colour. Ask to be told before the change, not after.
• Re-approve after any tooling change. New texture, re-polished cavity, new gate — all change appearance.

What Do You Do When a Batch Arrives Off-Colour?

Work in this order. Most disputes are settled at step 3, and the ones that are not usually turn out to be a reference problem rather than a production problem.

1. Put the batch next to the approved master, in the same light. Not a photo, not a chip, not memory. Daylight or the agreed light source.
2. Check whether the whole batch is off, or only part of it. A patchy difference points to masterbatch dispersion or mixed lots; a uniform difference points to the reference or the pigment lot.
3. Measure it. A ΔE reading from the same instrument type decides whether you are inside the agreed tolerance.
4. Compare against the retained reference, not the last shipment. If the last shipment was already drifting, you have been comparing to the wrong thing.
5. Decide: accept, sort, or remake. Inside tolerance and the product still works — accept with a note. Outside tolerance but usable at a discount — agree in writing. Outside tolerance and brand-critical — remake the affected quantity, and fix the process cause before the next run.

Whatever the outcome, write down the cause. A colour complaint that is not traced to a variable will happen again on the next order, and the second conversation is always less friendly than the first. If you are still at the stage of choosing a supplier, the questions in what an AQL inspection tells you are the ones to ask about incoming colour lots.

Related reading

Does Your Custom Cup Need a New Mould?

The arithmetic that decides whether to pay for tooling, and what actually moves a mould price.

What an AQL Inspection Actually Tells You

What the percentages mean, how many pieces get checked, and six things an inspection cannot see.

Customization Guide

The four layers you can change — colour and surface, logo, lid and accessories, packaging — and what each one costs in volume.