In a d/8° spectrophotometer, an integrating sphere provides diffuse illumination and the detector observes sample-reflected light at 8° from the surface normal. That geometry is useful when a controlled, repeatable color measurement is needed.
What an integrating sphere does in d/8° measurement
The sphere has a highly reflective inner coating. Light introduced into it is distributed by multiple internal reflections, creating diffuse illumination at the sample port. The instrument then observes the sample at the defined 8° viewing position and records the reflected spectrum.
01 / ILLUMINATE
Diffuse light reaches the sample
The sphere distributes illumination rather than shining from one single direction.
02 / CONTROL
Set the specular condition if supported
Compatible instruments may include or exclude the regular specular component as SCI or SCE.
03 / MEASURE
Observe at 8° and calculate color
The measured spectrum can be calculated into L*a*b*, ΔE and other values under the agreed conditions.
SCI and SCE are separate method choices
The 8° offset keeps the regular specular beam away from the normal viewing path and allows it to reach a controllable specular port or light trap. Closing or opening that port changes whether the specular component is included or excluded, which is the optical basis of SCI and SCE in compatible sphere instruments.
| Mode | What changes | Typical decision |
|---|---|---|
| SCI | Specular reflection is included. | Reduce the influence of gloss and texture differences on measured color. |
| SCE | Specular reflection is excluded. | Make the color result more sensitive to surface finish and appearance changes. |
Sphere-based designs can use the sphere differently in other instruments: for illumination, collection or both. An integrating sphere alone does not prove that an instrument offers SCI/SCE, transmission capability or a particular accuracy level—verify the model specification.
When d/8° is a strong fit
Paint and coatings
Useful for controlled solid-color work where the agreed SCI/SCE condition is part of the method.
Plastics
Useful for reflectance color checks on suitable mouldings, plaques and materials with controlled presentation.
Automotive solid colors
A practical option for defined solid-color methods; effect finishes may need specialised multi-angle or appearance capability.
Choose the measurement question first
An integrating sphere is not automatically better than 45°/0° geometry. Define whether your specification prioritises material color, surface appearance, angular color travel or another property, then choose a validated method. Continue with SCI vs SCE and d/8° vs 45°/0° geometry, or compare available spectrophotometers.
For technical background, see the CM-2600d/2500d principles of measurement.
Last reviewed 21/09/2026 · Level: Intermediate
Topics
Applications
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