Cerulean blue dark

Cerulean blue dark is a synthetic inorganic pigment powder sold by our supplier as cobalt(II) stannate (PB35), in a deeper shade than our Cerulean blue. It gives a strong, clear azure blue that is opaque, lightfast and stable to alkalis and lime, for oil, acrylic, tempera, watercolor, gouache and fresco.

Key facts

• Color: deep, clear azure blue
• Pigment type: Synthetic inorganic pigment (cobalt stannate)
• Colour Index: PB35 (C.I. 77368)
• Composition: cobalt(II) stannate, Co₂SnO₄ (supplier data)
• Origin: synthetic
• Opacity: opaque
• Lightfastness: 8 of 8 on the Blue Wool Scale (supplier data)
• Chemical resistance: alkali 5/5, lime 5/5, acid 5/5 (supplier data, 5 = best)
• Suitable for: oil, acrylic, egg tempera, watercolor, gouache, fresco (lime), lime and cement plaster
• Packaging: 25 g jar · 1 kg bag

How to use

Mull it into linseed oil, gum arabic, egg yolk or acrylic medium with a muller or palette knife. Like all ceruleans it has low tinting strength but good covering power, so it works best on its own or with white for skies, water and cool lights. Grind it gently. Some painters bind ceruleans in poppy oil to keep the blue clean. It is lime-proof and also suits silicate binders and concrete. Store dry in a closed jar.

About cerulean blue dark

Cerulean blue is cobalt stannate, first made around 1800 and sold to artists from the second half of the 19th century as "coeruleum", a name from the Latin caeruleus, "blue". It was used above all for painting skies. This dark grade gives a deeper azure than standard cerulean; our supplier lists the same composition and test values for both.

Safety

Contains cobalt compounds: may cause allergic skin or respiratory reactions; harmful if inhaled. Handle dry pigment with care: avoid breathing the dust and contact with eyes. Wear a dust mask (FFP2/N95) and gloves when working with the powder, work in a well-ventilated area and wipe up spills with a damp cloth. Do not eat, drink or smoke while working; wash your hands afterwards. Keep away from children and pets. For artistic and technical use only — not for cosmetics, food or tattoos.

FAQ

How does Cerulean blue dark differ from Cerulean blue?

Both are sold by our supplier as cobalt stannate (PB35) with identical test data. The dark grade is a deeper, more intense azure; Cerulean blue is a lighter sky blue.

Is it lightfast and suitable for fresco?

Yes. Our supplier rates it 8 of 8 for lightfastness and 5 of 5 for lime and alkali resistance, and cerulean is a lime-proof pigment.