Pantone, RAL and HEX: Turning a Color Reference Into Masterbatch

Color Reference Conversion

A buyer sends a Pantone number, a RAL code, or a HEX value and asks for a quote. The supplier replies with a price. Both sides assume they are talking about the same color. Then the first production batch arrives and it is visibly different from the reference. The dispute that follows is almost never about the supplier's ability to read a code. It is about the gap between a color reference and a production color specification.

This guide covers that gap: what each color system actually gives you, what data your supplier needs, how a factory converts a reference into a masterbatch formulation, and how to approve the color before mass production starts.

Why a Pantone or RAL reference is not yet a production spec

A color reference tells you what the color should look like under a defined viewing condition. It does not tell a compounder how much pigment to load into a specific resin, at what let-down ratio, for a specific part. Those variables change the result.

Four factors move the final color away from the reference:

• Substrate. The same pigment loading produces a different shade in PP than in PE. Resin base color, transparency and melt behavior all matter.
• Let-down ratio. A masterbatch dosed at 2% and the same masterbatch dosed at 4% will not match each other. The ratio is part of the color definition.
• Process and geometry. Injection molding, extrusion and 3D printing filament draw-down each orient pigment differently. Thin walls look lighter than thick sections of the same part.
• Surface finish. A textured mold surface scatters light and reads differently from a polished one, even with identical colorant.

This is why a reference code alone cannot be quoted accurately. It has to be converted into a formulation tied to your specific resin, process and part.

What each color system gives you and where it breaks down

Pantone, RAL and HEX are not interchangeable. Each was built for a different purpose, and each has a specific failure mode when applied to plastics.

System	What it defines	Where it breaks down for masterbatch
Pantone / PMS	A printed ink reference on coated or uncoated paper stock	Paper and plastic reflect light differently. The same PMS number looks different on a molded part.
RAL	A European industrial coating and paint standard	Formulated for paint films, not for pigment dispersed in a polymer melt. Gloss level changes the read.
HEX / RGB	A screen color defined by emitted light	Screens emit light; plastic reflects it. A HEX value is a starting point, never a match target on its own.

None of these systems is wrong to use. They are all useful as a starting reference. The mistake is treating any of them as the final acceptance criterion for a molded or extruded part. That criterion has to be a physical sample measured under controlled conditions.

What to send your supplier

The more of the following you provide up front, the fewer sample rounds you will need. A reference code with no context usually triggers a round of questions before work can start.

1. Reference code and system. State whether it is Pantone, RAL or HEX, and give the exact code. If you have a physical chip or swatch, send it.
2. Substrate and resin carrier. PP, PE or another polymer. If you already know the carrier you want, say so.
3. Process. Injection molding, extrusion, blow molding or 3D printing filament. Each has a different pigment loading window.
4. Part thickness. A nominal wall thickness in millimeters. Thin and thick sections of the same part will not read identically.
5. Surface finish. Polished, matte, textured or a specific mold finish. This affects perceived color more than most buyers expect.
6. Lighting condition. The light source under which the color will be judged, such as daylight or a specified indoor source.
7. Target quantity. Your expected order volume and any MOQ constraints you are working within.

If you are still deciding between a masterbatch, a pigment or a liquid colorant for the job, that decision comes before color matching. The comparison of masterbatch vs pigment vs liquid colorant covers how each option affects color control and process fit.

What the factory does with your reference

Once your data is in hand, the conversion follows a defined sequence. Understanding it helps you judge whether a supplier is doing real color work or just quoting a code.

Resin carrier selection

The carrier resin must be compatible with your base polymer. A carrier that disperses well in PP may behave differently in PE. Carrier choice affects dispersion quality and, in turn, color uniformity.

Pigment loading and formulation

The colorant package is built to hit the reference at your stated let-down ratio. This is where the reference code becomes a formulation: pigment types, loading levels and any additives needed for process stability.

Color chip and dispersion check

A color chip is produced and the dispersion is assessed. Poor dispersion shows up as streaks, specks or uneven color, and it will not be fixed by adjusting the shade alone.

Test plaque and colorimetric reading

A test plaque is molded from your resin at your let-down ratio. Colorimetric data is read from that plaque, not from the masterbatch pellet. This is the number that matters for approval.

For a worked example of how these variables are specified on a real product, the Universal White Color Masterbatch for PE/PP lists its TiO2 content, let-down ratio, brightness and yellow index as measured on polypropylene test plaques.

How to approve a color before mass production

Approval is a two-stage process. Skipping either stage is the most common cause of rejected shipments.

Stage 1: Sample plaque approval

You receive a physical plaque molded from your resin at your let-down ratio. Judge it under the lighting condition you specified, against your reference. Approve or request a shade adjustment in writing. Do not approve from a photo or a screen preview.

Stage 2: Colorimetric data and COA

Alongside the plaque, review the colorimetric readings. A certificate of analysis per batch should carry the color data together with the relevant physical properties, so the approved color is tied to measurable values rather than to a visual memory.

Stage 3: Batch-to-batch verification

First-sample approval confirms the formulation. It does not guarantee that every subsequent batch matches. Batch verification compares incoming production lots against the approved reference. The method for doing this is covered in Masterbatch Color Consistency: Verify Between Batches.

Common mistakes that cause color rejection

• Approving from a screen. A HEX value on a monitor is emitted light. The molded part reflects light. They will not match.
• Omitting the let-down ratio. The same masterbatch at a different dose is a different color.
• Ignoring wall thickness. Thin sections read lighter than thick ones from the same pellet.
• Changing resin after approval. A new carrier or base resin invalidates the approved formulation.
• Judging under the wrong light. A part that matches in daylight may shift under indoor lighting.
• Skipping batch verification. First-sample approval is not a batch-to-batch guarantee.

If your concern is mainly about order size and scheduling rather than color, the Color Masterbatch MOQ and Lead Time guide covers those terms separately.

FAQ