Satin Gold Interference Mica Pigment, 5–25μm – KT-201

KT-201 is a satin gold interference mica pigment in the fine 5–25μm particle size range — a natural mica grade from the KT-200 Interference Series with a thicker rutile TiO₂ coating than standard silver white grades, tuned to produce a gold interference color through selective light interference. At this particle size, the effect reads as a smooth, satin-character gold luster suitable for printing inks, fine cosmetics, and coating applications where a soft, even gold pearl finish is required. The gold interference color appears distinctly on dark or transparent substrates; on white or complementary-colored bases, the effect is significantly diminished — a substrate dependency that formulators must account for during development.

How Interference Pigments Work — and Why Substrate Color Matters

KT-201 uses the same mica-TiO₂ construction as the KT-100 Silver White Series, but with a thicker titanium dioxide coating. The increased coating thickness causes incident light to interfere constructively at specific wavelengths and destructively at others — selectively reflecting gold-phase wavelengths while suppressing the complementary colors. The powder itself appears white or off-white; the gold color only becomes visible when the pigment is applied over or into a dark or transparent medium.

This substrate dependency is the most important formulation consideration for interference pigments. Applied over black or dark substrates, KT-201 shows a clean satin gold interference color. Applied over white, the gold effect is largely lost — the white base reflects all wavelengths and masks the interference. Applied over a substrate color that is complementary to gold (violet-blue range), the gold reflection competes with the base and the result appears muddy or muted.

Conversely, a warm yellow or gold-toned base reinforces the gold interference — both the base color and the pigment's reflected wavelength are in the same phase, amplifying the visual effect. For formulators targeting maximum gold color impact, a dark or same-phase base is the correct specification.

Critical distinction within the Kolortek interference range: KT-201 and the broader KT-200 series are standard interference pigments — they show a single interference color on dark substrates. They do not exhibit the angle-dependent color shift (color travel) of chameleon or OVP pigments. A KT-201-coated surface appears gold at all viewing angles; it does not shift to another color. Buyers seeking color-travel or goniochromatic effects should specify Kolortek's chameleon interference series instead.

Technical Specifications

KT-200 Interference Series: Available Interference Colors

Note: All KT-200 series interference pigments appear white or off-white in powder form. The interference color is only visible when applied over dark, transparent, or same-phase base materials. Contact Kolortek to discuss which interference color suits your specific substrate and application.

Application Range

Formulation Notes

Base material selection is non-negotiable: Before specifying KT-201 for any application, confirm the base color or substrate transparency. White, light grey, or off-white bases will absorb the gold interference effect and leave a flat, colorless result. If your formulation requires a light or white base, consider combining KT-201 with a small amount of yellow or gold transparent pigment in the base to shift it into the same color phase — this technique partially compensates for the absence of a dark background.

Fine grade and printing ink compatibility: At 5–25μm, KT-201 falls within the particle size range used for gravure and flexo printing ink applications. Confirm your specific press nozzle and screen specifications against the D90 from the TDS before specifying for production ink — a confirmed D90 below 25μm is the standard requirement for most printing applications.

Mixing protocol: Add KT-201 at the letdown stage after all high-shear dispersion steps are complete. Use low-shear paddle mixing for incorporation. At 5–25μm, the fine platelets are susceptible to fracture from high-shear equipment — mechanical damage reduces D50 and shifts the interference effect toward a flatter, less saturated gold character.

Kolortek has produced the KT-200 Interference Series for over 20 years alongside the broader pearlescent pigment range, with consistent TiO₂ coating thickness control across production batches — the manufacturing parameter that most directly determines interference color accuracy. TDS, SDS, and INCI documentation are available on request for all grades in the series.

Frequently Asked Questions

Q: Why does KT-201 look white in the bag but gold in the finished product?
A: Interference pigments appear white or off-white as dry powder because the interference effect requires a dark or absorbing background to function — in the powder state, there is no such background. When the pigment is dispersed in a transparent medium or applied over a dark substrate, incident light passes through the TiO₂ coating, reflects off the mica substrate, and interferes with light reflected from the coating surface. Wavelengths in the gold range are selectively amplified; complementary wavelengths are suppressed. Without the dark background to absorb the non-reflected light, the interference effect is invisible.

Q: Is KT-201 a chameleon pigment? Does the gold color change with viewing angle?
A: No. KT-201 is a standard interference pigment — it shows a gold interference color on dark substrates at all viewing angles. It does not exhibit angle-dependent color shift (color travel). Chameleon pigments use a different multi-layer coating architecture that produces two or more distinct colors depending on the viewing angle. If you need a gold-to-another-color shift effect, specify Kolortek's chameleon interference series. KT-201 is the correct specification when a stable, single-color gold pearl is required across all viewing angles.

Q: Can KT-201 be used over a white base coat in decorative coatings?
A: The gold interference effect will be significantly reduced or absent over a white base. White substrates reflect all visible wavelengths, which counteracts the selective interference mechanism that produces the gold color. If a white background is unavoidable, applying a dark transparent toner coat between the white base and the KT-201 layer can partially restore the effect — but this adds a process step. For consistent gold effect performance, a dark or same-phase warm base is the correct specification.

Q: What is the difference between KT-201 (natural mica) and the KT-7200 synthetic mica equivalent?
A: The interference color and coating mechanism are the same — the difference is substrate purity and performance properties. Natural mica contains trace mineral inclusions that can appear as small dark specks in finished applications. Synthetic Fluorphlogopite (KT-7200 series) has higher substrate purity with fewer visible inclusions, better luster and chroma, improved weatherfastness, and higher thermal stability — relevant for plastics processing above approximately 500°C. For standard coating, cosmetic, and craft applications, natural mica KT-201 is adequate. For prestige cosmetics, precision printing, and high-temperature applications, the KT-7200 series is more appropriate.

Q: How does KT-201 differ from Kolortek's gold series pigments (KT-300)?
A: KT-300 gold series pigments use iron oxide or other colored coatings on the mica substrate to produce a warm gold color — the gold effect is visible on most substrates including light and white bases. KT-201 interference gold uses the TiO₂ thin-film interference mechanism — the gold color only appears on dark or transparent substrates. The interference gold is generally considered cleaner and more chromatic on appropriate substrates; the KT-300 gold is more versatile across different base colors. The choice depends on your substrate and the specific gold tone required.

Request Samples or Technical Data

Interference pigment performance is highly dependent on your specific substrate and application conditions — evaluating KT-201 on your actual base material before production specification is strongly recommended. Contact Kolortek to request a sample for application trials, download the TDS with particle size distribution data, or discuss interference color selection across the KT-200 series for your formulation.