SCI and SCE are two specular conditions used with integrating-sphere spectrophotometers. They do not change the paint; they change whether mirror-like surface reflection is included in the measured signal. That choice can materially change results on glossy, matte, orange-peeled or textured coatings.
What SCI and SCE mean
| Mode | Optical condition | Practical effect |
|---|---|---|
| SCI | Specular component included. | Reduces sensitivity to gloss and surface texture, supporting comparison of the coating’s material color. |
| SCE | Specular component excluded. | More closely follows appearance changes caused by gloss and texture as well as pigment color. |
It is accurate to say SCI reduces or removes the effect of gloss differences on color, but SCI does not exclude the specular component—it includes it. SCE excludes the specular component and therefore becomes more finish-sensitive.
How coatings respond
Two panels made from the same paint can produce similar SCI values but different SCE values if application or cure changes gloss or texture. If both SCI and SCE move in a similar direction, investigate pigment concentration, dispersion, film thickness, substrate and formulation. If SCE moves much more than SCI, inspect gloss, orange peel, levelling and surface contamination.
Choose the condition from the quality question
- Formulation and tinting: SCI is often more useful because it minimises finish variation while the color recipe is adjusted.
- Batch color consistency: SCI can separate material-color drift from process finish, provided the agreed method specifies it.
- Finished visual match: SCE can be useful when surface finish deliberately belongs in the color assessment.
- Customer specification: use the named condition. If none is named, align buyer and supplier before setting tolerances.
Use both modes without creating two specifications
Simultaneous SCI/SCE instruments can provide powerful diagnostic data. Designate one mode as the contractual pass/fail result and use the other as a process clue unless both limits are explicitly validated. Do not average SCI and SCE or compare an SCI standard with an SCE sample.
SCI/SCE is not gloss measurement
A difference between SCI and SCE may indicate surface influence, but it is not a gloss-unit value. Use the specified 20°, 60° or 85° gloss method when gloss itself must be controlled.
Write the complete method
Record geometry, SCI or SCE, aperture, illuminant, observer, color space, Delta E formula, UV condition, sample preparation, backing, orientation, locations and averaging. Keep the same conditions at every site. Continue with measuring glossy coatings, measuring textured coatings and the complete coatings guide.
Last reviewed 22/09/2026 · Level: Intermediate
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