In my current study of painting in acrylics, I’m finding the many options possible with this paint to be daunting! I’ve been working for a year, and nearly every day since November, and have so much yet to explore! One thing I’ve been thinking about is the beautiful transparency of certain colors (thalo blue, yum!). I know how I use transparency in oil painting, and it’s the essence of watercolor. But how do I want to deploy transparent paint in my new medium? The possibilities seem endless!
Back in 2008 I saw a local exhibition of landscape paintings. I recognized the unmistakable lushness of tree and vine, the murky undertone of the river water, and the yellow soils of the coastal plain of Maryland & Virginia. I really wanted to meet the artist. Ross Merrill was the chief conservator for the National Gallery of Art, and in his long career contributed a great deal to our knowledge of paint chemistry and the history of paint in art. He loved to paint plein aire along the lower Potomac River near his Virginia home.

I only had the chance to attend one workshop with Ross before his untimely death in 2010, and I am so grateful that I did. We spent a lovely long weekend out at Rehoboth Beach with Ross as he shared his plein-aire method. He told stories of painting adventures with Robert Gamblin, of the Gamblin paint company. These guys were pigment geeks, and had clear ideas about their favorite paints and tools. But the most powerful thing I learned from Ross was his use of transparent and opaque colors.
If you’re painting outside in oils, you face a number of challenges. Oils dry slowly (acrylics dry WAY too fast for my liking, especially outdoors.) Hiking with a wet painting is tricky if you want to return un-smudged! So how to set up for success in the great outdoors? A great solution is to use Alkyd paints. Alkyd resin is much faster drying than linseed oil. (It’s also incredibly tough; alkyd is the paint used for lines on the highway.) Ross was actually instrumental in convincing Gamblin to create a line of alkyd paints.
Ross’s plein-aire method was a two-day process. First lay down a ground of raw sienna (there’s that yellow soil, literally.) Develop your value structure using only transparent colors: Ultramarine, sap green, alizarin. Build up your darks and wipe out the highlights, letting that warm ground glow through. Add burnt umber to deepen your darks if needed. If you are working outside in alkyds, and by days end it will be tacky or even touch dry.
The next step will transform your picture: mix your sky colors, from zenith to horizon. Paint in your sky and bright reflections in those sky colors over the transparent underpainting. ‘Punch” holes in your trees, defining the leaves & branches.
I recreated this method last night on a pair of tiny canvas panels. By adding a slow-dry medium I was able to work the ground layer somewhat… it still dries too fast in acrylic!
I don’t know how I will ultimately use the awesome power of transparency in my acrylic painting. Stay tuned for examples of my experiments! But I wanted to share this method and remember a wonderful teacher who changed the way I painted.

This is so timely. Yesterday I painted my first acrylic painting in about 40 years and really felt like exploring it further.