Best mica powder and pigments for resin
Five kinds of colour that behave completely differently in epoxy, and five different ceilings. The one thing they share is that none of them takes part in the reaction.
Mica powder is the default and the one to buy first — pearlescent, cheap, and effective at 2% of the mix, with about 6% as the hard ceiling. Liquid pigment is the same ceiling and easier to dose. Alcohol ink is a solvent measured in drops and its limit is far lower than it looks. Glow powder is the exception at 10–20% by weight, because it is a coarse inert crystal rather than a fine platelet. Glitter goes by volume, because it is mostly air.
Nothing you stir into resin takes part in the reaction. Every particle of pigment, glitter or powder is inert filler that the curing resin has to build a solid network around, so there is a load past which there is simply not enough resin between the particles. It does not fail loudly — the pour just stays faintly soft, and the usual response is to wait another week for something that is already finished.
That single fact is why every colourant on this page has a ceiling and why the ceilings are not the same number. Mica powder and liquid pigment stop at about 6% by weight. alcohol ink fails at a much lower load and for the opposite reason. Glow in the dark powder runs at 10–20% and is a genuine exception rather than a loophole. Mixing them up is one of the causes of a pour that never stops being slightly soft.
The other thing worth knowing before you buy any of it: half a per cent of mica is already a solid colour. Almost everyone starts by using far too much, gets a muddy opaque casting instead of the pearlescent one in the photograph, and concludes they bought the wrong powder. The calculator has a pigment row that gives the weight for whatever load you set.
Five colourants, five ceilings
The last column is the typical dose on a real batch — coasters, set of 8, which is 691 ml of mixed resin. Note how small the mica figure is: this is a craft where a 50 g jar lasts a very long time, and where the commonest mistake is using ten times what you need.
What each one is actually for
Ground mineral coated to be pearlescent, and the reason most resin art looks the way it does. It is a platelet, so it catches light by lying flat — which is why the effect disappears at high loads, when there is no room for the flakes to orient. Cheap, endlessly variable, and it settles in a slow cure, so a deep pour needs stirring partway or the colour ends up on the bottom face.
Alcohol ink is a solvent carrying a dye, not a solid suspended in anything, so it fails for the opposite reason to a powder: the alcohol goes into the resin faster than it can flash back out, and what is left never builds full hardness. A piece over-inked stays faintly rubbery and dents under a fingernail. It is also the least lightfast colour here — alcohol ink fades in a sunny window within a year, which matters for anything sold. What it does that nothing else does is spread on its own: the cells, petri dishes and blooms that people buy it for are the alcohol moving through the resin, not a technique.
Three times any other ceiling here, and it has to be: below about 10% it barely glows at all. It gets away with it because strontium aluminate is a coarse, dense, chemically inert crystal rather than a fine platelet, so the resin still bridges around it. It also settles fast and hard — expect thin layers, or all the glow on the underside.
Choosing between them
Pre-dispersed color in a carrier, so it stirs in without clumping and will not settle the way a powder does. Same ceiling as mica for the same reason. A pigment sold for acrylics or for casting plaster is not the same thing and frequently will not cure. The practical difference is dosing and clumping: powder needs working into the resin properly and can leave streaks if it does not, and a dispersion stirs in immediately. Mica gives the pearl and the shimmer; a liquid pigment gives a flat solid colour. Both stop at 6% for the same reason.
Acrylic paint, plaster colourant and printer ink all turn up in resin tutorials and all bring water or a binder with them. Water is the problem: even a little leaves a cloudy pour that may never set hard. Buy colourant sold for epoxy, and check that mica is the resin grade rather than the cosmetic grade if it matters to you — they are the same mineral with different paperwork.
Two different chemistries at very different prices, and the cheap one is the reason people think glow powder does not work. Strontium aluminate charges fast and glows for hours; zinc sulfide is a fraction of the price and fades within minutes. If a listing does not say which it is, it is the cheap one. Both are used at 10–20% — far more than any other colourant here.
Measured by volume, because glitter is mostly air and a weight figure would be meaningless. Polyester glitter holds up in resin; craft glitter with a metallic coating can bleed its color into the pour. It sinks, so anything past a light load ends up as a stripe on the bottom face unless the pour is done in layers. Dosed by volume rather than by weight because it is mostly air — a bulk density of about 0.35 g/ml, so a percentage by weight would over-state the load by roughly threefold and read as safe when it is not.
Each colourant has its own ceiling, and they also add up. Two pigments at 3% each are a 6% load, and the resin does not care which jar the filler came out of. The calculator totals the inert load across every additive and warns on the sum rather than only on each row.
Not a ceiling but an absolute: UV resin cures by light, so anything that blocks light stops the cure at whatever depth it stopped. A heavy mica load or a white pigment in UV resin gives a set skin over liquid resin, permanently. The UV resin guide covers it.
Getting the colour you meant
Half a per cent of mica powder is already a solid colour on a clear resin. Weigh it rather than eyeballing it — 14.7 g on a 691 ml batch is the typical dose, and it is a scoop rather than a spoonful.
Stirring powder into an already-catalysed batch spends working time you do not have, and leaves streaks if you rush it. Disperse the colour into the resin side first, get it uniform, then add the hardener and do the three-minute mix. The clock only starts on the second step.
Colour in a cup and colour in a 10 mm casting are not the same colour — depth darkens it and the mold surface changes the finish. A few millilitres in a bottle cap, cured overnight, tells you what the batch will actually look like for the cost of nothing.
Mica and glow powder both sink in a slow cure. In a coating epoxy it barely matters; in a 10 mm casting with hours of pot life, the colour ends up on the bottom face. Stir gently once as it starts to thicken, or pour in thin layers, or use it deliberately — a settled layer is what a "sand" effect actually is.
6 drops per 100 ml is enough for a lot of effect, and ink is at its best dropped onto the surface of a poured layer rather than mixed through the batch. That is where the cells come from, and it uses a fraction of the ink.
A glow casting looks like nothing at all until it has had light on it. A minute under a lamp — including the UV lamp, if you have one for UV resin — is the difference between "this powder is faulty" and the effect you paid for.
Weigh the pigment rather than guessing it
Add a colourant row in the calculator and it gives the weight, the drop count or the volume for whatever load you set — and warns when the total inert load goes past what the resin will carry.
Open the epoxy calculator →Print the pour-depth card
Maximum pour depth and cure windows by resin type — the number that cracks a casting. Free.
Estimates, not advice. Every figure on this page is computed from published reference values and standard measures, so your own inputs, equipment and conditions will move it. Nothing here is professional advice — talk to a qualified professional before acting on it.