BUYER GUIDE / FOOD

Thermoformed Tray Color and Appearance Control Guide

Colour in thermoforming is influenced by the resin, the masterbatch, the sheet thickness, the forming stretch and the surface texture. A colour that matches on a flat sample can shift on a formed part because the wall thins and the surface changes. Colour approval should therefore use the actual formed part under agreed lighting, with the approved sample kept as the production reference.

Published and updated: 2026-08-25

Content author: Wenzhou Tonghou Plastic Products Co., Ltd.

04 / ENGINEERING NOTE

Colour is not a single number

A colour specification that works on flat sheet can fail on a formed part because thermoforming changes the material.

The base resin has a natural tint that interacts with the masterbatch, especially in lighter colours.
Sheet thickness affects colour depth: thin formed walls can look lighter or more translucent than the flat sample.
The forming stretch distributes material unevenly, so the same part can have slightly different colour density in deep and shallow zones.

05 / ENGINEERING NOTE

Surface and lighting change perception

The same colour on a glossy surface and a matte surface can look different under the same light.

Agree the lighting condition for colour approval—daylight, fluorescent or a defined standard.
Note the surface: a glossy formed area and a matte area on the same tray can appear to have different colours.
Compare the production part against the approved sample under the agreed lighting, not against a printed reference.

06 / ENGINEERING NOTE

Control colour across cavities and batches

Colour consistency is a production discipline, not a one-time approval.

Confirm the masterbatch direction with the material supplier and keep it stable across batches.
For multi-cavity tools, check colour across cavities because local forming conditions can shift the result.
For repeat orders, keep the approved sample under stable storage and compare under the same lighting each time.

Applications

Custom-coloured food and gift-box trays
Brand-colour matching for retail packaging
Multi-cavity trays needing consistent colour across cavities

Selection criteria

Resin and masterbatch confirmed for the colour direction
Colour matched on a formed part, not only on flat sheet
Lighting and viewing conditions agreed
Approved sample kept as the production reference

Pre-production validation

Match colour on the actual formed part under agreed lighting conditions. Record the masterbatch direction, resin grade and approved sample. For repeat batches, compare production parts against the approved sample under the same lighting.

04 / DECISION MATRIX

Buyer decision table

Colour factor	Why it matters
Resin	Base resin has a natural colour that affects the final result
Masterbatch	Colour concentrate must be compatible with the resin and food-contact if applicable
Thickness	Thinner walls show more of the base resin colour; thicker walls look deeper
Forming stretch	Material distribution changes optical density across the part
Surface	Glossy vs matte surfaces change perceived colour

05 / BUYER QUESTIONS

Common buyer questions

01Why does my tray colour not match the flat sample?

Thermoforming thins and stretches the sheet, changing its optical density. Colour should be approved on the actual formed part, not on flat sheet.

02Can I use a Pantone reference?

A Pantone or similar reference can set the target direction, but the final approval should be on the formed part under agreed lighting, because forming changes the colour perception.

03Why are cavities in the same tray slightly different in colour?

Local forming conditions, material distribution and surface finish vary across the tool, causing minor colour shifts that are evaluated against the functional requirement.

04How do I keep colour stable in repeat orders?

Keep the resin grade, masterbatch direction, approved sample and lighting condition stable, and compare each batch against the reference.

06 / SOURCE BOUNDARY

Official references

These sources define terminology, testing or acceptance methods. Citing a standard does not claim Tonghou certification and does not replace project-specific validation.

U.S. FDA — Food Types & Conditions of Use for Food Contact Substances

Reference scope：Reference for defining the food type and actual temperature or storage condition; it does not certify a finished tray.