Measuring spectral data provides a higher level of color accuracy than densitometry alone.
Spectrophotometers measure reflected or transmitted light across a light spectrum. The resulting data creates a visual curve. Spectral data is invaluable to anyone in the printing trades. Spectral measurements ensure that color is consistent across varying substrates and production processes. A densitometer checks density but does not see color, and this can often result in color variations that might not meet customer expectations.
A sphere spectrophotometer is the preferred measurement instrument for colors that have been applied to a textured surface such as textiles, carpets and plastics, as well as shiny or mirror-like surfaces, including metallic inks, printing over foil, and other highly glossy surfaces. A sphere instrument is able to measure the light reflected from these surfaces and will return measurements that are very close to what the eye would see when looking at that surface. Examples include items such as a textiles, painted or coated parts and injection-molded products. Reflective materials and metals are often observed in lighter surroundings to take advantage of their reflective nature. This means that in practice, sphere instruments are more versatile since they allow for the measurement of a color with or without the impact of its substrate’s associated surface effects.
Spherical spectrophotometers support color measurement across a wide array of materials, including textiles, wood, plastics, roofing and ceiling tiles, foils, metallic inks and aluminum.
0º/45º (or 45º/0º) Spectrophotometers
No instrument “sees” color more like the human eye than the 0º/45º spectrophotometer. This is simply because a human viewer does everything in his or her power to exclude the “specular component” (gloss) when judging color. When we look at pictures in a glossy magazine, we arrange position so that the gloss does not reflect back to the eye. A 0º/45º instrument, more effectively than any other, will remove gloss from the measurement dynamics and measure the appearance of the sample exactly as the human eye would see it. Because 45° instruments perceive color in the same way as the human eye, they are generally preferred for applications such as measuring color on smooth or matte surfaces. They are not necessarily the best choice for measuring color on glossy and reflective surfaces.
Over the past decade, automotive manufacturers have created and refined automotive coatings to present a unique experience when viewing a vehicle. They have experimented with special effect colors using special additives such as mica, pearlescent materials, ground-up seashells, specially coated pigments in order to produce a surface that shifts in color when viewed from different angles. Large and expensive goniometers were traditionally used to measure these colors until X-Rite introduced a battery-powered, hand-held, multi-angle instrument. Today, X-Rite portable multi-angle instruments are used by most auto makers and their colorant supply chain around the globe.