Red Pearl Interference Mica Pigment Powder – KT-215

KT-215 is a red pearl interference mica pigment from the KT-200 Interference Series — a natural mica grade with a medium-layer rutile TiO₂ coating that selectively reflects red-phase wavelengths through thin-film interference. The powder appears white in bulk form; the red pearl color becomes visible when applied over dark or transparent substrates. For cosmetics, nail lacquer, decorative coatings, and printing inks where a clean red iridescent pearl is the target effect, KT-215 delivers consistent interference color determined by coating thickness rather than dye or pigment chemistry — which means the color does not fade or bleed over time in the same way organic colorants do.

Substrate Dependency — The Critical Formulation Factor

Red pearl interference pigments function through selective light interference at the TiO₂ coating surface. The red wavelength is reflected constructively; its complementary color — green — is suppressed. On a dark or black substrate, the absorbed complementary wavelengths disappear into the base, leaving a clean red pearl effect. On a white or light substrate, all wavelengths reflect and the interference color is masked, producing a flat, colorless result. On a green base, the complementary suppression conflicts with the base color and the result appears muddy or desaturated.

The practical rule: specify KT-215 for dark, black, or transparent substrates. A warm red or burgundy base coat reinforces the interference red and amplifies the visual effect. Avoid green-toned bases entirely. If your application involves a light or white base that cannot be changed, evaluate a KT-300 series iron oxide red grade instead — those produce red color on any base color without substrate dependency.

What KT-215 Is — and Is Not

KT-215 shows red interference color on dark substrates at all viewing angles. If you need red-to-another-color angle shift, specify Kolortek's chameleon interference series. The two effects are mechanically and visually distinct.

Technical Specifications

Application Range

Formulation Notes

Base color selection — the single most important formulation decision: Confirm your substrate or base material color before specifying KT-215. Green-toned bases (including olive, khaki, and certain browns with green cast) must be avoided — the complementary color suppression mechanism will produce a dull, flat result. Dark brown, black, or deep burgundy bases work well. If you cannot change the base color and it is not compatible, consider a red iron oxide base coat beneath KT-215 to create a same-phase dark foundation.

Particle size and application method: The appropriate KT-215 grade depends on your application method. Fine grades (5–25μm) suit printing inks, cosmetics, and airbrushed coatings. Coarser grades produce a more pronounced individual-flake sparkle in epoxy, resin, and brush-applied decorative coatings. Contact Kolortek to confirm which grade is stocked and appropriate for your specific use case.

Mixing protocol: Add KT-215 at the letdown stage after all high-shear dispersion steps are complete. Low-shear paddle or anchor mixing for incorporation. Mechanical platelet fracture from high-shear equipment reduces D50 and degrades interference color saturation — the color becomes less chromatic and the pearl character flattens.

Kolortek has produced the KT-200 Interference Series alongside the full pearlescent pigment range for over 20 years, with controlled TiO₂ coating thickness uniformity as the manufacturing parameter that directly determines interference color accuracy and batch-to-batch color consistency. TDS, SDS, and INCI documentation are available on request.

Frequently Asked Questions

Q: Why does KT-215 look white in the container but red in the finished product?
A: As a dry powder, there is no dark background to absorb the complementary wavelengths that the interference suppresses. Without that absorption, all reflected wavelengths reach the eye and the powder appears white. When dispersed over or into a dark substrate, the green and other complementary wavelengths are absorbed by the background rather than reflected — leaving only the red interference wavelengths visible. The color is generated by coating physics, not by a dye or pigment colorant.

Q: Does the red color of KT-215 shift to another color at different viewing angles?
A: No. KT-215 is a standard interference pigment that shows red at all viewing angles on dark substrates. Angle-dependent color shift (where the pigment shows, for example, red at direct view and shifts to green or gold at a glancing angle) is a property of chameleon interference pigments, which use a different multi-layer coating architecture. If color travel is a requirement for your application, specify Kolortek's chameleon series and not the KT-200 standard interference range.

Q: Can I use KT-215 in a red nail lacquer over a white base coat?
A: The interference red effect will be significantly reduced over a white base — white reflects all wavelengths and prevents the green complementary suppression from functioning. For red nail lacquer where the final formula is applied over bare nail (which has some pink-to-flesh translucency), the interference effect is partially active but less saturated than over a dark base coat. For maximum color saturation, apply over a dark burgundy or black undercoat. Many nail formulation labs test KT-215 specifically over a black base to qualify the interference color before finalizing the formulation.

Q: What is the difference between KT-215 (natural mica) and a KT-7200 red pearl synthetic mica grade?
A: Both produce the same red interference color through the same TiO₂ coating mechanism. The difference is substrate quality: natural mica contains trace mineral inclusions visible as dark specks, particularly at coarser particle sizes. Synthetic Fluorphlogopite (KT-7200 series) has higher substrate purity, fewer inclusions, better luster and chroma, improved weatherfastness, and thermal stability above approximately 500°C. For standard cosmetic, nail, and coating applications, KT-215 natural mica is adequate. For prestige cosmetics and applications requiring high substrate purity, specify the KT-7200 series.

Request Samples or Technical Data

Interference pigment performance depends on your specific substrate — evaluating KT-215 on your actual base material before committing to a production specification is strongly recommended. Contact Kolortek to request a sample for application trials on your substrate, download the TDS with particle size data, or discuss grade and particle size selection across the KT-200 Interference Series.