Blue Pearl Interference Mica Pigment Powder – KT-225

KT-225 is a blue pearl interference mica pigment from the KT-200 Interference Series — a thick-layer rutile TiO₂-coated natural mica grade that selectively reflects blue-phase wavelengths through thin-film optical interference. Applied over dark or transparent substrates, it delivers a clean, saturated blue pearl effect without the use of dyes or blue colorants. The interference mechanism is substrate-dependent: base color selection is the primary formulation decision before specifying this grade, and pairing with complementary-colored (orange-yellow) bases will suppress the blue and produce an unsatisfactory result.

Product Positioning

KT-225 fills the blue color position within the KT-200 natural mica interference range — alongside gold (KT-201), red (KT-215), violet (KT-219), and green pearl grades. Within Kolortek's broader portfolio, it sits between the non-substrate-dependent colored mica series (KT-300 gold, colored mica) and the goniochromatic chameleon pigments. Choose KT-225 when a clean blue interference pearl on dark or transparent substrate is the target and substrate color can be controlled — and choose the chameleon series when blue-to-color-shift behavior across viewing angles is the requirement instead.

The Interference Mechanism — and the Substrate Rule

The thick rutile TiO₂ coating on KT-225 creates a specific optical path length that causes blue-wavelength light to interfere constructively. The complementary color — orange-yellow — is simultaneously suppressed. On a dark or black substrate, the orange-yellow wavelengths are absorbed into the base, leaving a clean blue pearl reflection. On a white base, all wavelengths reflect regardless of the interference, and the blue color is masked. On an orange or warm-yellow base, the complementary conflict produces a dull, desaturated result.

Practical rule: dark, black, cool blue, or transparent substrates produce the strongest blue interference. A cool navy or dark blue base coat in the same color phase amplifies the effect. Orange, amber, and warm-yellow bases are the interference suppressors for KT-225 — these must be avoided.

Base Color vs. Expected Effect

Technical Specifications

Application Range

Formulation Notes

Mixing protocol: Add KT-225 at the letdown stage after all high-shear dispersion is complete. Low-shear paddle or anchor mixing for incorporation. Mechanical platelet fracture from high-speed dispersers or ball mills reduces D50 and shifts the interference color toward a flatter, lower-saturation blue. Do not recirculate through tight-clearance pumps after KT-225 has been added to the batch.

Base color confirmation before development scale-up: Verify your substrate or base color against the complementary suppressor list before committing to KT-225. If your formulation uses a warm-yellow, amber, or orange base that cannot be reformulated, a dye-based or iron oxide blue pigment will provide blue color independent of substrate darkness. KT-225 is the correct specification only when base color can be kept dark, transparent, or cool-blue.

Kolortek has maintained consistent TiO₂ coating thickness control across KT-200 series production batches for over 20 years — the parameter that directly determines interference color wavelength and batch-to-batch color accuracy. TDS, SDS, and INCI documentation are available on request for all grades.

Frequently Asked Questions

Q: KT-225 appears white in the container — is this correct?
A: Yes. All KT-200 interference pigments appear off-white or white as dry powder. The interference color requires a dark absorbing background to function — without it, both the blue-reflected and orange-yellow complementary wavelengths reflect freely, and the powder appears white. When dispersed over a dark or transparent substrate, orange-yellow wavelengths are absorbed by the background, leaving only the constructively-interfering blue wavelengths visible to the eye. The color is generated entirely by TiO₂ coating physics, with no blue dye or colorant involved.

Q: Does KT-225 shift color at different viewing angles like a chameleon pigment?
A: No. KT-225 is a standard interference pigment that shows blue at all viewing angles on dark substrates. Chameleon pigments use a multi-layer interference architecture that produces two or more distinct colors depending on viewing angle — for example, shifting from blue to copper or blue to green at glancing angles. If angle-dependent color travel is a product requirement, specify Kolortek's chameleon interference series. The two effects are mechanically distinct and produce very different visual results in finished applications.

Q: Can KT-225 be used in a formulation with an orange or warm-yellow base color?
A: The blue interference effect will be significantly suppressed or absent over an orange or warm-yellow base. Orange-yellow is the complementary color to blue — the interference suppression mechanism targets exactly these wavelengths, and when they dominate the base, the competing reflections cancel the blue pearl effect. If a warm base color is unavoidable, a dye-based or coated-mica blue pigment that provides color independent of substrate absorption is a more appropriate specification than KT-225.

Q: What is the difference between KT-225 natural mica and a KT-7200 synthetic mica blue pearl grade?
A: Both produce blue interference through the same TiO₂ coating mechanism. The distinction is substrate quality: natural mica contains trace mineral inclusions that appear as dark specks, more visible at coarser particle sizes and under close examination. Synthetic Fluorphlogopite (KT-7200 series) offers higher purity, fewer inclusions, better luster and chroma, improved weatherfastness, and thermal stability above approximately 500°C. For standard cosmetic, nail, and coating applications, KT-225 natural mica is adequate. For prestige cosmetics or applications requiring high substrate purity, specify the KT-7200 equivalent.

Request Samples or Technical Documentation

Interference pigment performance depends directly on your substrate — evaluating KT-225 on your actual base material before production specification is the most reliable qualification step. Contact Kolortek to request a sample for application trials, download the TDS with grade-specific particle size distribution data, or discuss blue interference color options across the KT-200 series.