Rublev Colours Cobalt System Drier is a professional, concentrated drier designed to speed the drying of oil and alkyd paint films with fewer drawbacks than cobalt used alone. It is a carefully balanced blend of metal carboxylates in mineral spirits, containing 1% cobalt (an active surface drier) and 13% zirconium (an auxiliary through-drier), combined in proportions suited to oil painting practice.

Cobalt is a strong oxidising drier that can accelerate surface drying, but when used on its own, especially in thicker paint applications, it can contribute to wrinkling. By pairing cobalt with zirconium, this system promotes more even, complete drying through the paint layer, helping the film set faster and more reliably. Zirconium is widely used as an effective replacement for lead driers and is valued for improving through-drying, supporting gloss, and maintaining colour clarity in the dried paint film.

This makes Rublev Cobalt System Drier a smart choice for artists working with slower-drying pigments, painting in humid or cool conditions, building thicker passages, or needing faster handling times between layers.

Directions (usage rate)
Add 1 drop per 5 ml of paint (about 1 teaspoon). Always test to confirm the best amount for your technique, pigment load, and film thickness.

Key details

• Concentrated cobalt + zirconium system for oil and alkyd paint

• Cobalt content: 1%

• Zirconium content: 13%

• Appearance: dark blue liquid

• Size: 59ml (2 fl oz)

Health and safety
Contains petroleum distillates. Avoid skin and eye contact and avoid breathing vapour or mist. Use gloves and eye protection and work in good ventilation. Do not ingest.