Jarosite light

Jarosite light is the paler, brighter grade of our natural jarosite pigment powder, made from the potassium iron sulfate mineral jarosite. It gives a clean light yellow with a lemon note and, according to the supplier, covers better than the regular grade, which makes it useful for light passages and soft yellow mixtures in oil, egg tempera, watercolor, gouache and acrylic.

Key facts

• Color: light, bright lemon-yellow
• Pigment type: Natural mineral pigment
• Composition: jarosite, potassium iron sulfate hydroxide, KFe₃(SO₄)₂(OH)₆
• Opacity: semi-opaque (the supplier rates its covering power as high)
• Lightfastness: 8 of 8 on the Blue Wool Scale (supplier data)
• Chemical resistance: acid 5/5 (supplier data, 5 = best); not alkali-resistant (lime turns it into brownish iron hydroxide)
• Suitable for: oil, acrylic, egg tempera, watercolor, gouache
• Not recommended for: fresco (lime), lime and cement plaster (not alkali-resistant)
• Packaging: 50 g jar · 1 kg bag

How to use

Work the powder into linseed oil, egg yolk, gum arabic or acrylic medium with a palette knife or muller; it is a soft mineral and disperses quickly, so long grinding is unnecessary. Mixed with white it gives delicate warm light tones, and in watercolor and gouache soft light yellows. Do not combine it with lime, cement or other alkaline materials, which slowly turn jarosite brownish. Store the powder in a closed jar in a dry place, because long exposure to damp has the same effect.

About jarosite light

Jarosite is named after the Barranco del Jaroso in southern Spain, where it was first described in 1852. In nature its color ranges from bright light yellow to yellow-brown; bright yellow jarosite is relatively rare, and brownish yellow material is more common. The mineral forms where iron sulfides weather under acidic conditions and has been identified as a yellow pigment in ancient Egyptian painting, including Middle Kingdom work at Karnak.

Safety

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

What is the difference between Jarosite and Jarosite light?

They are the same mineral. Jarosite light is a paler, brighter yellow with higher covering power (supplier data); our regular Jarosite is a deeper yellow with medium covering power.

Can Jarosite light be used in fresco or lime plaster?

No. Jarosite is not alkali-resistant: wet lime slowly converts it into brownish iron hydroxide. For fresco, use a lime-fast natural ochre instead.

Is Jarosite light lightfast?

Yes. It is rated 8 of 8 on the Blue Wool Scale (supplier data).