Hi all, I have been using acrylics for several years but I actually want to switch to WS oils… I have bought 2 colors of Cobra brand ( Titanium white and primary Cyan ) and I really enjoy the rendering … But my problem is that it takes very long to dry… I didn’t use water, except that my brushes were wet before begining but my skies are not dry 12 days after I painted them…
So I think I must use a drying fastener medium … It doesn’t exist in the Cobra brand. Is it better to use for example Lukas medium or alkyd medium Liquin ? what do you think ?
Thanks in advance for your help 
I don’t have the answer to your question but you have made me curious about this brand WS oil. I tried W&N WS oils and I did not like them so just gave up on WS. I may go back and try the Cobra, depending on the answers you get in this thread. I have heard titanium white Cobra WS does take almost as long as traditional oils to dry but are very buttery like traditional oils. Did you find the consistency nice?
I have not either the ability to compare with other brands, but yes, it’s very buttery and I enjoyed how it could cover with an intense colour … with acrylics, I often have to use several layers to get the good result I want…
And I have found that tle drying medium exists but it is out of stock on the brand website https://www.jacksonsart.com/cobra-watermixable-oil-mediums , so in the french shop too …
I was also curious to try this brand because it was used by a painter that I appreciate : Richard Robinson
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Titanium white is long to dry, regardless of type of oil paint.
The Lukas Berlin (ws) fast-dry medium is an acrylic emulsion. Mix it into WS oils and It sets in 15 minutes. It is dry the next day, but because of the rapid set, I wouldn’t recommend it for anything except underpainting or canvas toning. (And I’m a Lukas Berlin fan).
Strange to say (because the Winsor Newton Artison colors are miserable to work with), Artisan Fast Dry works very well. That’s when used in both Lukas Berlin and Cobra. The downside is that it has an offensive hydrocarbon odor – the same as Liquin but not as strong.
It’s not overpowering, but the odor is counter to the whole reason for WS oils – to avoid nasty solvents.
The Weber Woil and the Grumbacher Max fast dry mediums didn’t speed up drying very much for me, and the Weber definitely had a pretty strong hydrocarbon odor about it.
If you’re going to experiment with the European primary colors: one thing to watch with Cobra and Lukas Berlin – the primary blue contains quite a bit of white, making it very hard to achieve dark colors when mixing with just the primary pigments.
The Berlin phthalo blue (PB 15:3) is the one to use, but it’s an EXTREMELY strong colorant. Lukas primaries go something like this on my palette: 9" snake of primary yellow, 4" snake of primary red, 1/2" snake of phthalo – that’s three piles of paint with about the same coloring potential.
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I have used water soluble oils for years. I like Graham’s Walnut Oil Alkyd as it has no solvents and washed out of brushes easily with Master’s brush soap. Also, it is made in the USA.I don’t know about how it would change the Cobra Brand, but it cut the drying time of Grumbacher Max by 50-75 % depending on color. I no longer use Max because the formula changed to a much oilier paint. I am still looking for a replacement.
With a much oilier paint I can’t add the Walnut OIl Alkyd without getting an oily paint I object to.
Thank you very much for your helpful reply … It’s a pity if Fast-dry smells but I think that I will be obliged to try… I will easely find the Artisan brand which is well known in France. Thank you also for advices about colors. Yes, when I switch to another brand, there is always colours thats suit and other no … It’s not easy… It would be fine to have samples like for beauty products 
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Hopefully my info is useful…
A couple of additional tips:
Using water as thinner. Treating plain water like conventional oil thinner, by dipping the brush in the water or adding many drops to a nut of paint, is less successful than using a spritzer (water atomizer such as you would use with acrylics).
Colors lighten when mixed with water, but they settle back to their original saturation when the water dissipates.
Artisan Thinner. Hugely overpriced. It’s 50% propylene glycol and 50% distilled water. Here in the States, you can get propylene glycol on eBay for ~$US 11 for 16 ounces. (~9 Eu / 474ml) including delivery. It’s better than water for 2 reasons: it seems to mix into the paint more completely and it definitely dries a lot slower than water alone.
Compatibility with acrylics:
Most WS paints are fully compatible with artists acrylics and acrylic mediums, although the reasons for mixing them are a bit puzzling. It might be a way to achieve some heavy impasto with heavy body acrylics. Drying time does speed up – as I said, the Lukas Berlin Fast Dry Medium (sold in the EU as Lukas Berlin Medium Nr. 3) is a watery acrylic medium.
Rosemary, you might actually be happy with Artisan. It’s the only WS that’s supplied in a non-buttery consistency… some colors in fact are so stiff that they are very difficult to squeeze out of the tube. Artisan does maintain a good selection of pigments, so that’s in your favor as well.
Thanks Dave, that is exactly what I am looking for! I put the tube in a plastic bag and let it sit in a container of hot water for 10 min. if I can’t squeeze it out. A usual problem with Titanium white especially.
Thank you !! just made the step and ordered 13 colours of Cobra, + the fastdrying medium and also the painting medium frop Artisan brand… Can’t wait now to receive the order and try to experiment 
Thank you for your tips … yes, I saw that just using water to thin the painting is not the good way …I have painted with oils, traditional oils 20 years ago and I used medium with oil to paint more fat at each new layer ( if I remember …)
I tried using cobra but they just wouldn’t dry during the humid months. literally 3 months had gone by and the paintings were still tacky.
I’ve been using Chroma Archival Lean Painting Medium with Cobra & Holbein WS oils for about 18 months now since taking a workshop with Colley Whisson (he uses regular Chroma oli paint–not water soluble paint). Really like it–tacks up under 2 hours; thin layers dry to the touch 1-2 days. Have tried mediums from Cobra, Holbein, and Daniel Smith and they are all very thick and gummy–Chroma’s is very thin consistency. Have also used Gamblin’s Solvent Free gel–convenient for plein air as it’s a paste consistency so no liquid cups to spill! As for WS brands, much prefer Cobra & Holbein to Winsor Newton Artisan BUT if you can get used to their smell and thick, thick consistency, they are a good value with impressive cadmium colors. Not sure if I had started with Artisan that I would have stuck with them–they are difficult to handle.