SCI vs SCE: What’s the Difference?

Accurate color measurement and evaluation are crucial in automotive, printing, textile and plastic industries. In these sectors, effective communication of color aids in brand continuity and helps to maintain quality control throughout different stages of production. It aids in maintaining standard operating procedures throughout the different levels of production.

Working with benchmarks such as Specular Component Included (SCI) and Specular Component Excluded (SCE) are significant in color measurement. Though these terms may be new to you, understanding their use in color measurement and gloss evaluation will help you make an informed decision concerning your needs.

Precise Color Communication

Communication of color represents the quantitative description of shades through instruments and colors expressed verbally. This advances to spectrophotometers and colorimeters that use light to measure the surface SCI and SCE values required in effective control. They help improve testing measurements, processes and outputs,

Color uniformity in SC paint and coated products goes beyond subjection to a tint. It also includes the final surface finish. Accurate measurement is vital, especially where gloss and texture tend to influence the perception of color.

The Difference Between SCI and SCE

Optical Structure of Integrating Sphere Colorimeter

SCI stands for Specular Component Included, and it differs from SCE in that both diffuse and specular reflectance are measured. A special component is referred to as gloss surface mirror reflections. SCE is Specular Component Excluded which focuses on diffuse reflection and ignores gloss mirror parts.

The geometric conditions are abbreviated as follows:

D/8 °: i - diffuse illumination, observation angle of 8 °, including mirror light; That is, SCI or SPIN;

D/8 °: e - diffuse illumination, observation angle of 8 °, excluding mirror light; That is, SCE or SPEX;

Ask yourself this question, what is responsible for separating diffuse reflection from specular reflection?

● A possible answer can be: Specular reflection occurs when light bounces off the surface of a polished item at certain feasible angles.  

● Scattering of light in certain angles in the presence of rough surfaces results to a phenomenon known as diffuse reflection.

The most paramount distinction between SCI or SCE is the incorporation of mirror-like reflection. SCI captures accurately objective color value, whereas SCE shows how people see color in everyday situations.

SCI and SCE in Color Measurement (Including & Excluding Specular Component)

There are inaccuracies associated with either SCE or SCI spectra measurements when calculating color values:

●  Specular Component Included measurement (SCI) calculates the color value of the surface being measured, which on the pigment level means the intrinsic color of the material being analyzed.

● Specular Component Excluded measurements (SCE) do not include a glossy surface’s specular reflectance. Therefore, the results from this measurement correlate better with the actual head rather than the glossy surface.

The Lab values of plastic sheet measurements in SPIN mode are comparable, while the data differences in SPEX mode are consistent with visual perception

These techniques are essential for industries where gloss and surface finishes color visually alter a person's perception. For instance, several objects may show identical SCI values while there is a noticeable difference to an observer because the surface finish differs.

SCE helps detect these perceived differences

For highly glossy items such as shiny plastic or metallic paints, the angle of incidence of light or specular light will greatly change the appearance. Neglecting specular portions in the light could cause a major visual difference in the color to be overlooked.

There are corresponding design requirements for the glossiness of automobile instrument panels. If the surface glossiness of the instrument panel is too high, it will cause glare and reflections on the windshield, interfering with the driver's vision. At the same time, excessive specular light entering the driver's eyes can easily cause driver fatigue, which will seriously affect driving safety. Therefore, in the process of color control, engineers can determine the real color of the material in the SCI mode, while the color data obtained in the SCE mode is consistent with the visual perception.

SCI and SCE in Colorimeters

The purpose of color difference meters or colorimeters is to measure the deviation of a standard color to a sample. In this case, the SCI vs SCE selection is important:

● For SCI mode, it uses pigment-based differences which is suitable for raw material or formulation work.

● In SCE mode, it captures perceived differences due to gloss or texture which is best for examining the final product.

For instance, in sci instruments, suppose a plastic toy has the right pigment, but as a result of some post processing steps, the surface finish does not match the approved sample. In that case, SCI would “accept” the part, but SCE would reveal the mismatch during final inspection.

This is the rationale behind using both SCE and SCI modes together. In this way, both chemical and visual discrepancies can be evaluated.

SCI vs SCE

To summarize the SCI vs SCE debate:

With every approach, there are specific objectives to be achieved. The SCI approach assists when uniformity of raw materials is the priority. You want SCE when the concern is what the customer sees versus the company product specifications.

Color and Gloss (SCI and SCE Method)

Color and gloss go hand in hand. Based on the surface’s reflection, it may appear lighter or darker. Here, the term specular becomes crucial, secularity describes the degree to which a surface is reflective or mirror-like.

Using SCI measurements helps standardize results by eliminating variables caused by gloss or texture. On the other hand, SCE reveals how much gloss affects color perception.

These days, many industries combine both methods for greater efficiency:

● SCI color serves as a base for formulation and blending processes.

● SCE color is used for visual appearance checks during packaging and pre-shipping.

This approach narrows the gap between technical color matching and perception in the real world.

SCI/SCE in Spectrophotometer

Modern spectrophotometers have dual measurement capabilities, seamlessly switching between SCI/SCE modes. These devices are more sophisticated and flexible. Below is an overview of application for SCI and SCE modes:

● SCI: A beam of light strikes the object, then all light (specular and diffuse) is collected. Measurement of materials with uniform internal color, such as plastic pellets or fabric dyes, is straightforward with these tools.

● SCE: The mirror-like reflection is blocked using optical traps or light-bending methods, permitting only diffuse light to reach the sensor. This is useful for determining how a person would look at a product in some normal room light.

The colourimeter with an SCI/SCE integrating sphere structure, designed and developed based on market demand, is widely used in the automotive interior industry. This is because it can accurately measure the real color and perceived color of diffuse reflection components with different gloss levels. Whether in the design stage or the quality control stage, this direct and efficient digital color management solution is highly favored by engineers. If we talk about analyzing sci paint samples or shiny metal parts, spectrophotometers that toggle between SCI and SCE provide complete color performance analysis.

Final Thoughts

Understanding the differences between SCI and SCE methods is critical to achieving optimal color accuracy. The SCI method assures color measurement is neutral and uniform, while SCE improves the methodology by considering gloss or surface finish and how human observation adds value. Apply SCI during moments where technical rigor and internal quality control demand unassailable precision. Apply SCE during moments when customer impression and product face value is critical.

Combined with trustworthy SCI instruments, knowing when and how to apply each method thresholds ensures an accurate pair alongside strong visual appeal. The combination of both methods, understanding specular reflectance, diffuse vs specular, and specular vs diffuse reflections empower industries to strengthen color quality control and improve customer satisfaction.