Three finishes change as the hand moves, and they are often sold under one another's names. A holographic polish throws a rainbow. A duochrome slides from one colour to a second. A multichrome moves through three or more colours as the angle changes. They look related on the nail, and they use different physics in the bottle.
The difference matters when you buy. A holographic top coat over a crème gives a rainbow flash; it does not change the base colour. A multichrome over black gives a colour change; it does not show a rainbow. Knowing which pigment does what saves a lot of disappointing swatches.
What is holographic nail polish?
Holographic nail polish is a lacquer that contains tiny silver particles coated with a surface that diffracts light into a colour spectrum. Chemist and science educator Michelle Wong describes them as silver particles with a coating which splits or diffracts the light into a colour spectrum, in her Lab Muffin guide to holo polish. White light is made of many colours, and the coating separates them the way a rainbow or the back of a CD does.
The coating works as a diffraction grating. It has a regular pattern of microscopic grooves. When light hits the grooves, each colour bends by a slightly different amount, so the reflected light fans out into red, orange, yellow, green, blue and violet. The colour you see depends on where the light comes from and where your eye is.
The commercial pigment is Spectraflair, an aluminium-based flake made in several particle sizes. The number in a name such as Spectraflair 15 refers to the particle size of the pigment, as noted in the Lab Muffin comments. Smaller particles give a finer, smoother rainbow.
What is the difference between linear and scattered holo?
Linear holo shows a rainbow that sweeps across the nail as a single band. Scattered holo shows colours that change abruptly, like small rainbow sparks. The difference comes from how smooth the pigment layer is, according to Lab Muffin: the smaller the particle size and the denser the polish, the smoother the holo layer, and the more linear the effect.
Repeated brushing can reduce linearity. In Lab Muffin's test with a Spectraflair top coat, extra coats and repeated brushing during application disturbed the smooth layer and made the rainbow less linear. For a linear holo, apply thin coats with as few strokes as possible and let each coat set before the next.
Both types are sold as toppers and as full colours. Holo Taco launched with separate scattered, linear and flakie holographic top coats at $13 each, as reported by Tubefilter. Lab Muffin names Nubar Reclaim, the China Glaze OMG collection and Nfu-Oh 61 as linear holos, and China Glaze Kaleidoscope and Milani HD as scattered.
How do duochrome and multichrome pigments work?
Duochrome and multichrome polish use interference pigments. An interference pigment is a transparent platelet, usually mica, synthetic mica, silica or borosilicate glass, coated with a very thin film of a high-refractive-index material such as titanium dioxide or iron oxide. The description of effect pigments on Wikipedia lists exactly these substrates and coatings and attributes the colour to reflection, refraction and thin-film interference.
Interference works like this. Light reflects from the top of the thin coating and from the bottom of it. The two reflections travel slightly different distances. For one colour they line up and reinforce each other; for other colours they cancel. The reinforced colour depends on the thickness of the film and on the angle of the light, so the colour changes as the nail turns.
Duochrome is the term for a pigment that shifts between two colours. Multichrome is the term for a pigment that shifts through three or more, made possible by multiple coating layers of tuned thickness. The two names describe the same mechanism at different levels of complexity, which is why brands use them loosely.
Diffraction or interference: what is the visible difference?
Diffraction always produces the full spectrum in order, because a grating bends every colour. That is why holographic polish looks like a rainbow whatever the base colour. Interference produces one colour at a time, chosen by the film thickness, so a duochrome or multichrome looks like a solid colour that changes, much like the surface of an oil slick or a soap bubble.
Diffraction depends on the light source. In direct sunlight or under a single bright lamp, a linear holo shows its sharpest rainbow. In diffuse daylight it looks like a soft silver shimmer. Interference pigments show their shift in almost any light, because the colour comes from reflection at a given angle, not from a point source.
Both pigment types are transparent or silver in themselves. The base underneath decides how strong the effect reads. Holo is usually sold in its own silvery base or as a topper. Interference shifts read best over black, which is why nail communities call a black base coat undies: the black absorbs stray light so only the interference colour comes back to the eye. Cirque Colors lists its Shimmergraphic and Spotlight Shimmers ranges in this family on its site.
Holographic vs multichrome vs duochrome: the comparison
| Finish | Pigment and mechanism | What you see | Best base | Example shades |
|---|---|---|---|---|
| Holographic, linear | Fine aluminium flakes with a diffraction grating coating (Spectraflair), a smooth dense layer | One rainbow band that sweeps across the nail in direct light | Its own silver base, or a topper over any colour | Nubar Reclaim, China Glaze OMG, Nfu-Oh 61, Holo Taco Linear Holo Taco |
| Holographic, scattered | Larger or less evenly laid diffraction particles | Rainbow sparks that change abruptly, softer in diffuse light | Any colour; reads as a sparkle topper | China Glaze Kaleidoscope, Milani HD, Holo Taco Scattered Holo Taco |
| Duochrome | Coated mica or glass platelets, thin-film interference, one coating tuned for two colours | A solid colour that slides to a second colour at the edges | Black or a deep crème | Cirque Colors Spotlight Shimmers range |
| Multichrome | Multi-layer interference platelets tuned for three or more colours | A colour that moves through several hues as the hand turns | Black, or self-opaque in two to three coats | Cirque Colors Shimmergraphic range, India Anaïs Aurora (violet to gold) |
India Anaïs Aurora is a multichrome that shows violet face-on and turns to gold at the edges. It is sold out with the first edition; the next edition is planned for spring 2027.
How do you apply each finish for the strongest effect?
Holographic: use a base coat, then two thin coats with the fewest brush strokes you can manage. Let each coat set for one to two minutes before the next. A glossy top coat is fine; a thick one softens the rainbow slightly, so apply it thin. Sunlight is the best place to judge the result.
Duochrome and multichrome: start with one coat of black crème, let it dry, then one or two thin coats of the shifting polish. Self-opaque multichromes take two to three coats on their own. Cap the free edge, because interference pigments are flaky and lift at the tip if unsealed. A top coat deepens the shift and does not dull it.
Removal: both pigment types come off with ordinary remover. Interference flakes can cling more than crème pigment, so press a soaked pad on the nail for ten seconds before wiping. A base coat keeps the black undies from staining the plate.
“they're silver particles with a coating which splits or diffracts the light into a colour spectrum”
Michelle Wong, Chemist and science educator, Lab Muffin Beauty Science
- Holographic polish diffracts light into a full rainbow; duochrome and multichrome reflect one colour at a time by thin-film interference.
- Linear holo needs small particles and a smooth, dense layer; scattered holo comes from larger or uneven particles.
- Duochrome shifts between two colours and multichrome through three or more, using the same coated-platelet pigment.
- Holo looks best in direct light on its own base; interference shifts look best over a black base and show in any light.
- Apply all three in thin coats with few strokes, cap the free edge and finish with a thin glossy top coat.
Questions people ask
Is holographic the same as multichrome?
No. Holographic pigment splits light into a rainbow by diffraction, so you always see a spectrum. Multichrome pigment reflects one colour at a time by interference, so you see a colour change as the angle moves. They are different pigments with different looks.
What is the difference between duochrome and multichrome nail polish?
Duochrome shifts between two colours, for example green to purple. Multichrome shifts through three or more, for example violet to gold to green. Both use coated platelets that work by thin-film interference; multichrome has more coating layers.
Why does my holographic polish not look holographic indoors?
Diffraction needs a strong single light source. Under diffuse indoor light the rainbow spreads out and looks like a silver shimmer. Take the nail to a window or under a single lamp and the rainbow returns.
Do multichrome polishes need a black base?
Not always, but a black base makes the shift much stronger. Black absorbs stray light so only the interference colour comes back. Self-opaque multichromes work alone in two to three coats; sheer ones need the black.
What is linear holo?
Linear holo is a holographic finish where the rainbow appears as one band that sweeps across the nail. It comes from very small diffraction particles in a smooth, dense layer. Scattered holo, by contrast, shows separate rainbow sparks.