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……

Water and Oil DO Mix: Cobra Water Soluble Oil Paints

I’m traveling most of the summer to teach and paint and I didn’t want to mess with Odorless Mineral Spirits (OMS). When I got an email from Royal Talens about their COBRA Water Soluble Oil Paints I thought I would give them a go and see what would happen. I placed an order with Jerry’s Artarama buying a warm and cool each of yellow, red, and blue, plus viridian, titanium white, and sienna. I also bought a burnt umber and black from Holbein’s water soluble Duo.

Tubes of Royal Talens Cobra

Cobra comes in 2 ranges: Professional and Student. While the tubes look very similar, the black cap indicates the professional grade and an orange cap the student grade. I only bought the black cap, but a friend gave me some samples of the student grade which included a Yellow Ochre which you can see in the photo.

Both professional and student grades of paint carry the exact same pigment. And according to Royal Talens, this is true for all brands of paint, whether it be water soluble, or traditional. So what is the difference?? The difference between a professional tube and a student grade tube is the amount of oil and filler used. Professional grades have a higher pigment ratio, which generally translates to more bang for your dollar.

What makes an oil paint water soluble? An emulsifier is added and blended in to the carrier mixture (oils and fillers) that allows water to be used instead of OMS to thin paint and clean brushes. An emulsifier is used when you want to mix oil and water, which normally don’t mix, allowing the particles to stay in suspension, and therefore to stay mixed. Water Soluble Paints are oil paints. They are intended to work exactly the same as a traditional tube whether you are glazing, working alla prima, or coming back later work on a piece. In fact, you can mix up to 30% of water soluble with traditional oils without losing the water soluble properties. Above 30% you will need OMS or something similar to clean up with. So let’s say you are using water soluble oils and you run out of a water soluble color and only have traditional oils available. You can absolutely use your traditional oils. But you may need to use OMS instead of water depending on how much traditional oils you end up using. Additionally, the rule of fat over lean applies to Water Soluble just as it does to traditional oil paint.

Next up…….Testing the colors