Sunday, September 22, 2019

Cold Wax Medium and Plein Air Painting

Season of Storms I
8x10 oil/cold wax - available

In my last post, I gave an overview of Gamblin's Cold Wax Medium.  I've used it mostly in the studio until now.  I always like to try new things in the studio before heading to the field where time is an issue.  In the studio, I found that CWM offers endless possibilities with collage and layering as well as additive (building up) and reductive (scraping down) methods of painting.  But what about outdoors?

One of the benefits of CWM is that it is a paste.  It will stay on your palette where you put it, unlike some other mediums (Galkyd Lite) that run and require a cup.  I dislike cups because they have to be cleaned, and if you have one with a screw-on lid and you don't clean it, the lid seems to get welded tight.  And then the cup gets thrown away.

Two other benefits.  CWM will thicken the paint and also make it more translucent.  These are properties I'm more likely to benefit from in the studio.  In the field, I want the paint to flow easily and not thicken, unless I'm using a painting knife rather than a brush.  Since I'm painting alla prima, getting the painting complete in more or less one session, I'm not looking at translucency as a benefit so much as I am at transparency.  I like my shadowed areas to be transparent to give them more depth; sunlit areas I make more opaque.  I suppose translucency might be factored in, and maybe it would be good to apply CWM over the shadowed areas to increase the sense of depth.

One concern I had with going outdoors was heat.  CWM is basically just beeswax with Gamsol and a little alkyd resin.  At room temperature, it is a paste; when the Gamsol evaporates, CWM becomes as hard as a beeswax candle. (The surface is actually quite durable.) The melting point of CWM is 155°F, which seems high, but it will soften as it approaches that temperature.

Block-in before using Cold Wax Medium

When I went out on a sunny day to paint with CWM, the air temperature was about 62°F.  I set up in the full sun.  At 7000 feet altitude, where I live, even in mid-September the sun can be quite intense.  I don't know how warm my palette got, but the sun was beating down on it.  My palette is the smooth wooden one that comes with the Guerrilla Painter 9x12 pochade box; I've used it for years, but I wipe down my working area faithfully so you can see the bare wood, which is a yellowish mid-value.  Around the outer edge, where I place fresh paint, I don't wipe it down clean, so there is always some dried paint there.  Using a knife, I placed a couple of dabs of CWM on the right side, where the wood is a bit darker because of some old paint.  Because this area is darker, it absorbs more light from the sun and gets warmer than the rest of the palette.  The dabs of CWM became noticeably less pasty and more fluid as they warmed up.

My container of Cold Wax Medium is in the upper right;
the dabs of CWM are on the right side of the palette.

Toward the finish

For the block-in, I didn't use any CWM at all but Gamsol to thin the paint just enough so I could get coverage.  In  the next and succeeding layers, I used CWM in every mixture, using my brush to pick it up and add it.  The CWM never got so fluid that it ran, but because it had softened in the heat, it really made the paint flow nicely.

Now, a day later, the painting is just a little tacky and is nearly dry.  The surface has a consistent matte finish to it.  When it's completely dry, I can varnish it with another layer of CWM.  Another option is Gamvar, which is fully compatible with CWM.

Will I use CWM outdoors regularly?  I'm not sure yet.  The other products I use outdoors - Galkyd Gel and Solvent-Free Gel - work just fine for me.  I may end up using CWM just in my studio practice, where I can take full advantage of its properties.

Season of Storms II
8x10 oil/cold wax - available

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