Three usual causes. You painted it over white or a light ground, and mica reflects whatever sits behind it, so any metallic that lets light through goes chalky over a pale surface. You scrubbed it on in every direction, which scatters the mica flakes instead of aligning them, so brush in one consistent direction. Or you thinned it with too much water, which separates the mica from the binder. Thin with an acrylic medium rather than water if you need it looser.

That depends on how much this one covers, and Metallic Violet is semi-transparent. A metallic that lets light through is at the mercy of its ground: over black or a deep violet underpainting it flares properly, and over white or raw canvas it goes pale and chalky. One that covers in its own right is far less fussy and will shimmer straight over a light surface, though a darker ground still deepens it. Either way, let the ground dry completely before laying the metallic over it in one or two even coats.

Yes, all Amsterdam acrylics are intermixable, but adding an opaque colour to a metallic buries the mica flakes in solid pigment and reduces the shimmer. If you want a metallic version of another colour, glaze a thin layer of Metallic Violet over the opaque colour once it is dry rather than mixing the two on the palette. Mixing metallic into metallic works fine and is a good way to shift the tone.

Royal Talens states that Amsterdam acrylics contain no animal-derived ingredients and are not tested on animals. Pigments and binders are synthetic or mineral. If this matters for a specific colour or for a school or institutional purchase, ask us and we will get the current safety data sheet and manufacturer statement for that exact product code rather than giving you a general answer.

If you are in Melbourne, our Moorabbin store carries the Amsterdam range on the shelf, and you can use Click and Collect to reserve online and pick up, usually ready in 1 to 3 business days. If you are in Brisbane, our West End store stocks it too. Everywhere else in Australia, we ship direct from our warehouses with tracking on every order, and Express Post reaches most metro areas in 1 to 2 business days after dispatch.

Oil over acrylic is fine, and is a standard technique. Acrylic gesso and acrylic underpainting make a perfectly good ground for oils. Acrylic over oil is not fine. Acrylic is a water-based film and will not bond to an oily surface, so it will sit on top and eventually peel. The rule painters use is fat over lean: acrylic first, oil on top, never the other way around.

Virtually any slightly porous surface: stretched canvas, canvas board, acrylic and watercolour paper, cardboard, MDF, plywood, raw and primed timber, stone, terracotta, plaster, concrete and rendered walls. It is alkali resistant, which is why it holds on masonry and render where many acrylics fail. Non-porous surfaces such as bare metal, glass and glossy plastic need an appropriate primer or adhesion promoter first, or the paint will lift.

It can, though it takes mistreatment. Signs are a sour smell, visible mould on the surface, lumps that will not redisperse, or paint that has separated with a watery layer on top that will not stir back in. Contamination from dirty brushes and palette scrapings is the usual cause, along with a lid that never sealed properly. A skin on the surface is normal, just lift it off rather than stirring it in.

Three things. Thin the paint slightly with a flow improver rather than water, so it levels instead of holding the mark. Use a soft synthetic brush or a foam roller rather than a stiff hog bristle. And build the colour in two or three thin coats rather than one thick one, letting each dry. Amsterdam's medium viscosity levels reasonably well on its own, which is why it suits flat graphic work better than a stiff heavy body paint does.