Cobra Oil Paints: The First Tests

This is part 2 of my series on Water Soluble Oil Paints. To see part 1, please go to. “Oil and Water Do Mix: Royal Talens Water Soluble Oil Paints”.

Now that I had my COBRA Water Soluble Oil paints and Holbein DUO I was really excited to try them! For the test I chose what are called single pigment colors, meaning that there was only one pigment used to make the color in the tube. For example, a Cadmium Yellow (PY35) is a single pigment but Cadmium Yellow Deep (PY35/PO20) is not. I wanted single pigments because part of what I was testing was how clean the colors were and how well they played with the other colors on my palette.


I painted the tests on YES! canvas.

Every tube of paint has its own feel and texture and this is true from brand to brand and color to color. COBRA’s consistency is really nice. It is creamy. It is also slightly ropey. I don’t know how else to describe it. Maybe a bit like the way mercury rolls around in your palm?…..(Remember those days??) But then not exactly like that either. The paint is a bit slippery when I went to pick it up with a brush, but totally workable. And after a couple of days I didn’t notice any difference from what I had been using, which was primarily Rembrandt, Holbein, and Windsor Newton. (Rembrandt is also made by Royal Talens)

The colors stay true whether they are wet or dry. Water soluble oil paints have a reputation of becoming dull. There is no dulling at all. In fact, wet or dry the color was exactly the same.

COBRA Color Swatches

They also have a reputation of being sticky on the palette when water is added. I didn’t find that to be the case at all. Adding water felt the same as when I would add OMS or any other medium to traditional oil paints. COBRA mixes very cleanly, lightens up well with white and the colors are truly lustrous when mixed with each other. The paint holds brush marks very well, but not like an impasto. They thin really nicely with water just as an OMS would thin them but it didn’t have the crazing that sometimes happens with OMS. The thinned colors were clean and looked like watercolor. (You can see it on the right side of the swatches) My brushes rinsed easily and cleaned up well. When I let my water sit for a couple of days the paint dropped to the bottom of the liquid just as they do with OMS. So far just as advertised and I could see potential!

The Cons:

The Cons of the paints was in the drying time. It really took ages and ages. When I started the tests the weather was cool and damp. After 4 days the paint was still very, very tacky. I didn’t make very thick marks and any other paint would have pretty will set up and dried by day 4. If you want a long workable time then this can be an advantage. But for travel I was worried that the long drying time might be a problem.

Thinking maybe it was the brand, I bought two earth colors, Burnt Umber and Burnt Sienna, and a Quick Drying Medium from Holbein DUO. Unfortunately it didn’t speed up the drying time at all. The DUO paints, colors that normally dry very quickly, also took a long time. I’m not at all sure why. Even when my weather warmed up (I live in Southern California…..warm, minimal humidity… the paint stayed wet for days.  Maybe it was the surface I was painting on??? Anyway, I’ve contacted Royal Talens and they are sending me samples and formulas for me to test.

In the meantime, I’m sticking with Cobra and hoping for the best. I am travelling for 3 weeks, half the time in a colder and damper climate of Scotland, and the other half in a hot, dry area of southern France.  If my paintings stay wet I will use waxed paper between the paintings to help protect them.

I’ll keep you posted……

2 thoughts on “Cobra Oil Paints: The First Tests

    • Hi Chloe…Thanks for asking….
      In Cobra Paints I have:
      Yellows: Cad Yellow Lemon, Permanent Lemon Yellow, Permanent Yellow Medium, Yellow Ochre
      Reds: Pyrrole Red, Primary Magenta
      Blues: Ultramarine , Cerulean Blue, Turquoise
      Greens: Phthalo Green, Emerald Green
      Orange: Burnt Sienna

      In Duo Aqua Oils by Holbein I have:
      Raw Umber, Ivory Black, and Mineral Violet

      I use these both by themselves, though not that often, and intermixed with traditional oil paints.

      When I was at the Plein Air Convention last year in San Francisco I had the opportunity to speak with the Cobra rep which helped to clear up some questions for me. The biggest was how water affected the paints. He told me that water acts as a quick drying medium in that the paints set up super fast when using water. I wanted the paints to be more juicy and thinnable without the fast (read that as stickiness) set up associated when I used water. He gave me their medium which is specific for water soluble oils called Water Mixable Quick Drying Medium. It says ‘new’ on the label. I’ve used it both for water soluble and traditional. I like it, but I have a medium that I make which I primarily use with traditional oils. That’s a 50/50 mix of Gamsol and Linseed Oil.

      I hope this helps! And if you want more info about my painting practice and teaching, you may want to consider going to my website and subscribing to my newsletter,



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