Oil Mediums


Last week on my Instagram story I took a poll to which more than 70% of you didn’t know that adding water to thin down oils was an art “no no.” It’s not because the all-powerful art gods said so, its because it’s really bad for the oils, and not a valid way to clean or use your tools. Here’s why adding water to oil paints isn’t the best choice for your art.

Adding water to oil paints has a lot of negative impacts to expensive oil paints. This makes sense when we remember that oil and water are, by nature, repellants. They do not mix well. Have you ever made a salad dressing and noticed how the oil, vinegar, and water all separate at different levels? They all have different weights and chemical components. When we add water to oil paints a few things happen.

  1. The oil paints will become foggy and lose their luster in color. Oil paints are known for being exceedingly rich in pigments and when water is applied it destroys that bright rich color by making it foggy which destroys its intended luster.
  2. Water on oils gets clumpy and difficult to work with. If you’ve ever tried to wash an oil brush with water (as I once did at 10 years old) you’ll realize that it is impossible to clean the paint clumps up and the mess just spreads.
  3. It will not bond as well to your surface. When water is added to oils, being that they are natural repellants, over time this combination will break down faster and cause your work of art to dissolve over time much more quickly than with a medium applied.
  4. You cannot clean oil paint off with water. Your tools will not be clean and you’ll ruin brushes.


What mediums should you use to thin or thicken oil paint? I’m glad you asked, here are some options for you! I will break this down into oil thinners and oil thickeners.


  1.  Neo Megilp
    This medium increases transparency & flow and makes if feel silky when you brush it across a canvas and it gives colors a satin gloss. It takes about 3-4 days for this medium to dry.
  2. Solvent-Free Gel
    This medium makes the paint move through your brush and on to the canvas with an ease of flow. It also makes the colors more transparent while still maintaining the shape of the brushstrokes and increasing the gloss. It will take about 3 days for this medium to dry.
  3.  Galkyd
    This oil medium will thin and increase the transparency of the colors. It will also smooth out brush strokes depending on how much you use and what your desired effect is. This medium dries the fastest in about 1-2 days.
  4.  Galkyd Slow Dry
    This does the same thing as the regular galkyd above, however it takes longer to dry. Why would someone want to take longer to dry, some people like long drying times so they can continue to work on at their piece over a longer period of time. It will take about 4 days for this one to dry so you can take your merry time!
  5. Galkyd Lite
    This one is the same as the first galkyd but it will also keep your brush strokes if you don’t use too much. It’s more fluid and has less gloss than regular galkyd. It will dry in 1-2 days.
  6. Refined Linseed Oil
    Linseed oil will increase flow across the canvas and majorly slow down dry times. Increases flow and slows dry time. Use it sparingly and use with gamsol. This medium will dry in 4-6 days.
  7. Cold Pressed Linseed Oil
    This medium slows the drying time and increases yellowing. (booo I hate this one because of the yellowing) but that’s a personal choice. Will take about 4-6 days to dry.
  8.  Poppy Oil
    Poppy oil is probably the slowest drying medium. It is great for wet techniques. It should also be used sparingly and with gamsol. Will dry in 4-6 days.
  9.  Gamsol
    This is probably the safest medium, it thins oils and used to clean your utensils. It is reusable and non-toxic, this is probably what I used the most when I was doing oils in high school.
  10. Turpentine
    Real Turpentine is made of spirits of Gum Turpentine. It is the distilled product of the sap of a pine tree. It has a very strong smell. Traditionally used to clean your brushes and tools.
  11. Turpenoid
    Is a petroleum distillate and comes from drilled oil. It’s smell, color is less harsh than Turpentine. Traditionally used to clean your brushes and tools.

Both Turpentine and Turpenoid are good for cleaning brushes, but they can be used as solvents if used combined with either linseed, stand, or walnut oil. People can be very sensitive to both Turpentine and Turpenoid. Turpentine for example makes my eyes burned if I’m exposed for too long.



  1. Cold Wax Medium
    This medium makes oil paints thicker and more matte. It also works as a varnish if you’d like to make your oil painting more matte. It takes 4-6 days for this medium to fully dry.
  2. Galkyd Gel
    This medium dries quickly and increases transparency. This is a thickening medium and holds brushstrokes and increases It will dry in a day or two.


I’m sure I missed a few, but essentially what I am trying to say is, almost anything is better than water to thin your oils. Please do not do it. It hurts my heart to know that people out there are thinning oils with water. Have any questions about mediums? Or do you have a favorite of these mediums? Tell me below!

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  1. During my schooling I used Liquin as my main medium. However, after school I started to use the Neo-Megilp and Cold Wax Medium. I mix them together to create a medium that is buttery and thicker. However, the wax does dry to a matte finish and the Neo-Megilp gives the wax a slightly glossier appearance.
    I’ve enjoyed using both, but as I’ve just started using these two mediums, I am worried about their archival quality. Additionally I am lost when it comes to applying the “Fat over Lean” principle with thes two mediums.
    In general I wants create areas of texture in my work, but not necessarily to the point where it could be classified as an “Impasto” approach. My intent in using this mixture of the two mediums was so that I could make something that offered both a better flow when painting and more body to the paints.
    I’m curious if anyone has ever mixed the Galkyd Gel with the Neo-Megilp. If so, what was it like? Are they compatible?

    1. Author

      I have not tried that combo. If you try it let me know what you find! I’m always interested in learning new techniques!

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  3. Hi Christine,
    I recently started an oil painting using only Gamsol for the underpainting. I mixed 3 primary colors(burnt sienna color) as a preliminary tonal canvas wash & proceeding to firm up the values, putting in the darks/mid tones & wiping out the ‘lights’ of the canvas using gamsol without white. I had initially intended to do an alla prima painting & wanted to work wet into wet allowing ‘about’ 3-4 days to dry. I had never used Gamblin Solvent Free Gel before, but proceeded into color application with a little bit of white to help tone colors & keep within the value range I had established in the monochrome underpainting. The following day I had realized the painting was already tacky to the touch(to the point I’ve had to give it an additional 1-2 days to fully dry now, before proceeding).The gel has also given the painting ‘a bit’ more sheen/shiny gloss than I’d like. I’ve seen ‘some’ glossy paintings I like, however mine seems to have a ‘little distracting shine’ to it, particularly under a light source. How can I proceed after it’s fully dry now? What medium + gamsol would be best suited for 3-4 more days of wet on wet paint application so I can also achieve more free flowing paint than straight from the tube + ‘knock down’ the glossy sheen ‘just a bit’ at the same time? Thank You for your time & consideration! God Bless, Ron M.

  4. I am having a hell of a time with many paintings yellowing from using neo Megilp.. they are all beach paintings done very quickly so there are spots where I use the white of the canvas. After about nine months I’ve noticed these spots especially are very yellow.. it looks terrible, when I used to be a beautiful painting.. wtf gamblin! Maybe a little heads up?! It looks like mustard! I’m not happy.

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