Color measurement in plastics is a process-control discipline, not a single instrument reading. Resin grade, pigment and masterbatch dispersion, filler loading, moisture, thermal history, crystallinity, wall thickness, texture and gloss can all change the measured or perceived result. A useful programme therefore defines the sample, optical geometry, settings, presentation and decision rule together.
Start with the form of the plastic
| Sample | Recommended method direction |
|---|---|
| Opaque plaque or moulded part | Reflectance with fixed geometry, aperture, orientation and measurement locations. |
| Translucent part | Controlled backed reflectance when appearance over a backing is the requirement; transmission when transmitted color is the requirement. |
| Clear film, sheet or plaque | Transmission color, with path length and specimen position controlled. Measure haze separately when it matters. |
| Pellets or granules | A repeatable cup, depth, packing and sampling method; do not assume pellet color predicts the finished part. |
| Textured or glossy surface | Define orientation, aperture and specular condition. Treat gloss as a separate appearance property where required. |
Build one controlled measurement method
Document the instrument geometry, SCI or SCE condition, illuminant and observer, color space and difference formula, aperture, calibration routine, sample conditioning, backing, orientation, number of readings and sampling locations. The standard and production sample must be measured under the same conditions. If suppliers use another instrument, establish correlation before relying on a shared numerical tolerance.
Follow the material through production
Incoming pellets and masterbatch can provide an early warning, but the final decision should normally be made on a representative plaque or finished part. Moulding and extrusion can change thickness, dispersion, orientation, cooling rate, crystallinity and surface replication. Retain a protected master standard and verified working standards so production teams are not comparing against a worn or contaminated reference.
Plastics measurement guides
- How to Measure Color on Plastics
- Measuring Injection-Moulded Parts
- Measuring Plastic Pellets and Granules
- Measuring Masterbatch Color
- Measuring Textured Plastics
- Measuring Glossy Plastics
- Measuring Transparent and Translucent Plastics
- Delta E Tolerances for Plastic Parts
- Choosing Spectrophotometer Geometry for Plastics
- Color QC for Plastic Suppliers and Manufacturers
Match the instrument to the decision
Portable d/8 instruments such as the SD-500 and SD-700 UV suit many opaque-part workflows. For transmission color, haze and more controlled benchtop presentation, consider the SD-800B or SD-900B. Confirm capability against the actual sample, aperture and required method before purchase.
Technical foundations
Use the guides to SCI vs SCE, measurement geometry, aperture size, Delta E tolerances and instrument agreement for the technical principles behind the application workflow.
Last reviewed 21/09/2026 · Level: Intermediate
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Related knowledge
Measurement Techniques
How to Measure Color on Plastics
Start plastic color measurement by choosing reflectance or transmission. Backing, thickness and orientation then become controlled method conditions.
Quick technical guide · Read the guide →Measurement Techniques
Measuring Injection-Moulded Parts
Measure injection-moulded plastic parts with controlled locations, orientation, backing, conditioning and process context so color data represents production.
Technical guide · Read the guide →Measurement Techniques
Measuring Plastic Pellets and Granules
Measure plastic pellets and granules with representative sampling, controlled cup depth, packing and repeat preparations while keeping pellet and final-part specifications separate.
Technical guide · Read the guide →Measurement Techniques
Measuring Masterbatch Color
Control masterbatch color by defining whether pellets, a standard let-down plaque or the final polymer application is the release specimen.
Technical guide · Read the guide →SCI & SCE
Measuring Textured Plastics
Measure textured plastic parts with a sufficiently large aperture, controlled orientation, multiple locations and a defined SCI/SCE condition.
Technical guide · Read the guide →SCI & SCE
Measuring Glossy Plastics
Measure glossy plastic color with a fixed specular condition, clean handling, controlled orientation and a separate gloss requirement where appearance depends on both.
Technical guide · Read the guide →