ColorXpress* Services uses an instrument called a spectrophotometer to measure colors. A spectrophotometer produces a reflectance curve that can indicate the color being measured. White light contains all the colors of the rainbow in the visible spectrum.

When white light falls upon an opaque object, the object interacts with that light. If the object appears red it is because the object absorbed most of the white light selectively, reflecting only the red portion, which is observed by the eye.

Likewise, if an opaque object is green, it absorbs all of the white light except the green portion. White objects produce a reflectance curve which is essentially flat at nearly 100 percent (reflecting all wavelengths), and black objects produce a curve which is essentially flat at nearly 0 percent (absorbing all wavelengths). For transparent objects the process is similar, except the white light is selectively absorbed, transmitting (rather than reflecting) only the color observed. This interaction accounts for all the colors visible.

Many single pigments and pigment mixtures can be identified by their spectrophotometer curves. Reflectance curves are like fingerprints. Each chemical variety of a pigment or dye has its own specific spectrophotometric fingerprint.

In many cases an experienced colorist can “read” a spectrophotometer curve, leading to the identification of the colorants contained in an unknown sample. ColorXpress* Services colorists use this knowledge and SABIC’s proprietary FormTool artificial intelligence software to select colorants and develop the color formulations for each color match.

The following factors or items may cause differences in color and appearance between the standard and color match:

• Dissimilar polymers or colorants introduce Refractive Index differences.
• Differences in surfaces between standard and color match.
• Similar polymers from unlike sources may introduce differences.
• Different compounding and fabrication processes may introduce differences.
• Additives may affect colorant dispersion and appearance properties