Does anyone know if there is an intermediate varnish available for watersoluble oils? I haven’t found any and have been using the varnish that is meant for normal oil colours (by Winsor&Newton). I have only used it a couple of times and am a bit worried if it can have some negative effect on the watersoluble paint. A few days ago I applied for the first time a final varnish over an intermediate varnish. The final varnish was for watersoluble paints (by Winsor&Newton again). I noticed that after the varnish had sat for a while it started to separate into droplets on the painting surface. I went over the work with a rag and it looked better after that. Do you think this is normal? Or can it be that the different types of varnishes repel each other as they are meant for different types of oil colour?
Once water mixable oils are dry to the touch, all soap (un-fancy term for the surfactants that make them water-soluble) has evaporated or has been converted.The result is that they are just like traditional oils at that point. Anything for traditional oils should work.
If you have thinned your water-soluble varnish with water, it will bead up on dried oil paint, water-soluble or traditional.
That said, there are conditions where varnishes will bead on dried oil paint. It has to do with surface tension (but nothing to do with whether there was a surfactant in the paint at the time the paint was applied.) This usually can be prevented by knocking back a bit of the gloss on the paint (or varnished surface), usually with sandpaper or by rubbing with pumice or other mild abrasive. Brisk rubbing with a clean rag will have the same effect.
Back in the bad old days, when house and wall paints were oil-based, you always had to sand your undercoats or first coats before applying a second… same thing applies to oil.
By the way, final varnishing should be delayed until the oil paint (again, whether water-soluble or traditional) has been exposed to air for 6 months or more. Linseed “dries” by reacting with oxygen in the air - it polymerizes. The polymerization has to be well advanced between final varnish is a good idea. Varnish prevents oxygen from reaching the paint film.
If you’re using W&N Artisan, you might try a tube or two of Cobra or Lukas Berlin. There’s a world of difference in consistency and working behaviors. I found Artisan to be sticky and stiff.
Dave, thanks so much for your answer!
You know a lot about this subject, thank you for sharing. This helps me
immensely and is a relief to hear.
I’ve been waiting 6 months
before applying the final varnish. I only put the intermediate varnish
on those that are sold before I can put on the final varnish. Thanks
again for the tips on avoiding the beading. I haven’t thinned the
varnish with water but still it beaded up.
A month ago, I
bought a few tubes of Cobra and made the same observation: the
consistency is much nicer. I always have to spend a long time with
Winsor and Newtons thinning them to a workable consistency.
Hopefully it will be of some help. Water-mixables are tough to understand in general. Conservative artists tend not to like them… in the same way that medieval navigators didn’t like the idea of a round earth - just too new an idea. It’s also a bit hard to understand a soap that will evaporate (technically, they’re ether alcohols) – in a short period of time, once out of the tube, water-mixables pretty much turn into standard, old-fashioned oils and you can’t mix water into them any more.
For more on the varnish problem, try doing a Google search on “varnish beading up.” You’ll find lots of people with the same problem (whether artists in oils, water-mixables, acrylics; or owners of boats, floors, and other commonly-varnished surfaces)… and lots of good information about how to avoid it.
Thanks so much, you gave a lot of important information about oils that was new to me! It’s especially good to know that water does not work as a thinner when the paint has started to stiffen.
I am very happy that these water-soluble paints were developed, I hadn’t even thought of trying oils before as I knew the solvents would make me nauseous.
To understand how watermixable oils work, I suggest you check out the wonderful YouTube videos on Cobra watermixable oils. There are 8 videos and they are great. He explains every aspect of how the chemistry of water mix able oils work. Many questions are answered with these videos.
Thanks so much for this tip! Very helpful videos, really recommendable.
I wonder if the ether gives off any fumes to worry about.
Not sure why, but I was loving the cobras then noticed that the paintings were staying tacky. I thought that the artisan paints were not consistant. I really like the holbien duo except Im all out.
I have had good luck with just regular W/N retouch varnish for oils. And I don’t have to wait for a year for it to dry.