Table 2 Acid values of the linseed oils
From: Reconstructing Van Gogh’s palette to determine the optical characteristics of his paints
Oil | Acid value (mg KOH/g oil) | Remarks |
|---|---|---|
Hydraulic pressed oil—raw | 0.61–0.89 | Results of 9 measurements, oil kept in different conditions for a few months (light, dark, closed and open vessel) |
Windmill pressed oil—raw | 2.8–3.0 | Results of 11 measurements, oil kept in different conditions for a few months (light, dark, closed and open vessel) |
Windmill pressed oil—washed | 3.7 | Average of duplicate measurement |
Commercial refined linseed oil for oil paints | Max. 1 | Alberdingk-Boley, Germany |
Raw linseed oil for paints | Max. 6 | Daniel Morrissey Order, 1949, Ireland |
Non-acid refined linseed oil for paints | Max. 4 |