Optical Properties - Noble Metals Property Model Settings

The Intercritical annealing checkbox is selected by default. It is where the Model can either accept the given composition as a homogeneous FCC solid solution or perform an equilibrium calculation at the temperature specified under Condition Definitions to get the phase fractions.

This is an important setting as intermetallic phases have a very important effect on the actual color of the alloy.

• When selected, an equilibrium calculation is performed at the specified temperature and the composition and uses the calculated equilibrium phase and composition for optical property simulation.
• Click to clear the checkbox if the specified composition is used directly and the alloy contains only FCC phases without phase separation.

Select the Calculate ΔE value checkbox if there is a target color and you want to know the difference between the calculated alloy color and targeting color. Then choose a ΔE method: CIE 2000 (default), CIE 1976, or CIE 1994.

See About DeltaE (ΔE) in the theory section for more background detail about these settings.

Based on the ΔE method selected, further define these settings.

See About Color Space in the theory section for more detail about the options.

• Color space of targeting color: Select LAB (default), sRGB, or XYZ. Then define the index to calculate ΔE, where the range of space for each setting is: LAB [0, 100], sRGB [0, 1], and XYZ [0, 1].
• Enter values into the 1st, 2nd, and 3rd index fields based on the Color space of targeting color selection:
• First index of targeting color: X for XYZ, L for LAB, R for sRGB.
• Second index of targeting color: Y for XYZ, a for LAB, G for sRGB.
• Third index of targeting color: Z for XYZ, b for LAB, B for sRGB.

Enter a value for the Incident angle [degree] between 0° and 90° for the incident light angle. The default is 0° (normal light). Incident angle is the angle at which light strikes a surface. This angle is measured between the incoming light ray and the normal (a perpendicular line) to the surface. The incident angle plays a crucial role in determining how light interacts with a material, which in turn affects the perceived color of the material.

Select an option from the Standard illuminant list. Choose the incident light wavelength distribution, such as standard daylight illuminant D65 (the default).

See About the Standard Illuminant in the theory section for more detail about the options.

Select the View angle of observer: CIE 1931 2 Degree Standard Observer or CIE 1964 10 Degree Standard Observer (the default).

In general:

• CIE 1931 2 Degree Standard Observer is most accurate to view small objects or when details are seen up close, such as tiny pixels on a screen or small color samples.
• CIE 1964 10 Degree Standard Observer is better for measuring color in typical situations where larger objects are viewed, such as printed materials, paints, textiles, or any larger surface.

See About the Viewing Angle in the theory section for more detail about the options.

Enter a value for the Material thickness [nm]. The default is 10000 nm.

This is and important setting when dealing with thin films or coatings.

Material thickness plays a significant role especially in the context of thin films, coatings, and transparent or semi-transparent materials. It affects how light interacts with the material, influencing reflection, transmission, absorption, and interference effects, all of which contribute to the final perceived color of the material. For example, a several nanometer thin gold film may display red or orange color, and it shows gold color when the film is thick enough. The default thickness is 10000 nm which displays bulk properties. The calculation assumes the two sides of materials are both air.

Choose the Color space for the resulting color space index 1-3: LAB (default), sRGB, or XYZ.

See About Color Space in the theory section for more detail about the options.

• LAB (the default) includes all visible colors and is ideal for color matching, quality control, and any application where accurate perceptual color differences matter.
• XYZ covers all perceivable colors and is best for scientific and colorimetric studies, where precise color representation and transformations are needed.
• sRGB has a smaller color gamut, but it is widely used for displaying on consumer electronics