Holbein DUO Aqua Oil Color is a versatile, water-soluble oil that is richly pigmented, lightfast and quick drying (in as little as 24 hours in some cases). In addition, it has all the characteristics of traditional oil colors, but can also be mixed with water and other water-based media to produce varying effects. When mixed with oil colors and mediums, DUO Aqua Oil dries to a uniform sheen and will retain its water-solubility as long as the oil color or medium content does not exceed 30%. When mixed with water, DUO dries to a matte finish and should be used with a stainless steel or plastic painting knife. These Holbein Duo Aqua Oils Whites come in 150ml tubes.