All Amsterdam acrylics are intermixable, and Cobalt Blue (Ultramarine) behaves predictably in mixes given it is semi-opaque. Start by mixing it with titanium white for tints and with a small amount of its complementary colour to knock back the intensity rather than reaching for black, which tends to deaden a mix. Keep a swatch card of your mixes with the ratios written on it, because you will want to repeat one later.

Cobalt Blue (Ultramarine) is rated +++ on Royal Talens' scale. Three pluses means the colour is rated to last at least 100 years under museum conditions, two pluses at least 25 years. Museum conditions means indoors and out of direct sunlight. That rating is why work painted in Amsterdam Standard Series is safe to sell, provided the buyer is not hanging it in a north-facing window.

The Amsterdam Standard Series runs in 20ml, 120ml, 250ml, 500ml and 1 litre, though not every colour is made in every size. We carry the sizes that move, and the 500ml jar is the one to choose when you are painting large, teaching, mixing in volume or working on murals and props. If you want a size you cannot see on the site, ask us and we will check what Royal Talens produces in that colour.

The honest comparison is on three things: permanence, consistency and range. Amsterdam Standard Series carries ++ or +++ lightfastness across the line, has a medium buttery viscosity that holds a brush mark without being stiff, and runs to around 90 colours including metallics, reflex fluorescents and specialty finishes. Some competing student ranges are thinner, some are stiffer, and several carry fewer colours or do not publish lightfastness at all. If a range will not tell you its lightfastness, that is the thing to notice.

Yes, we ship to New Zealand. Orders are charged in Australian dollars, and import duties, taxes and levies charged by New Zealand are not included in the order total or the postage and are the recipient's responsibility, so check locally before you order. We are not currently shipping to countries other than Australia and New Zealand.

Not as freely, because acrylic sets fast, but you can get close with the right approach. Work wet into wet quickly and in small areas, keep a mister handy, and use an acrylic retarder or an open medium to extend the working time. The alternative approach, which often looks better, is to build the blend in thin glazes once each layer is dry, letting the transitions happen optically rather than physically.

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.

Yes. Schools, universities, community art programmes and studios are a large part of what we do, and the 500ml and 1 litre sizes exist for exactly this reason. If you need quantities across multiple colours, or a quote on school letterhead, contact us rather than working through the cart and we will put it together properly, including availability and lead time on anything we would need to bring in.