• Oil Medium, also known as Liquin, is an additive mixed with oil based paints to either thin or thicken the texture of the paint and slow or speed up drying time.


  • Oil Medium may be composed of linseed, poppy, safflower, or petroleum based oils. 1, 2 Cultivation of plants requires water, fertilizer, and possibly pesticides. Petroleum based oils are a product of the fossil fuels industry.


  • Cultivation of flax, poppy, and safflower is efficient, since the plants have numerous commercial uses, including as textile fiber, edible seeds, opioids, seasoning and natural textile dye, however land must be cleared for plant agriculture. 3, 4, 5 Plant based oils are made from renewable resources, while petroleum based oils are not, and must be extracted from the earth. The petroleum industry contributes to loss of habitat and global warming.

Human Health

  • Plant based oil mediums are considered safe for human use, with many of the same oils used for cooking. 6 Petroleum oil mediums are hazardous, causing skin reaction and possibly cancer. 2, 7 Since medium is used in combination with toxic and irritating oil paints, precautions should be taken to avoid exposure, regardless of the medium’s toxicity.

Social Equity        

  • Poppy cultivated for its oil may also be used to create opium products such as morphine and heroin, which are controlled substances with high potential for abuse. 3 In the case of Afghanistan, the nation’s economy is dependent on poppy cultivation and heroin production. This has upset traditional village leadership and led to high levels of addiction. 8

Safe Use and Exposure

  • Wear gloves and breathing protection to avoid exposure to irritating oils.

Proper disposal

  • Dispose of unusable oils in the designated hazardous waste bins. Do not pour down the drain. Donate usable materials to the givetake.

Safe Alternatives

  • Use plant based oils which carry a “AP Certified Nontoxic” label.


  1. “Winsor & Newton Drying Mediums for Oils”, Blick,
  2. Winsor & Newton Liquin Original MSDS,
  3. Papaver Somniferum, Wikipedia,
  4. Safflower, Wikipedia,
  5. Flax, Wikipedia,
  6. Winsor & Newton Drying Linseed Oil MSDS,
  7. “2-Butanone, oxime”, PubChem,
  8. “Opium production in Afghanistan”, Wikipedia,