I first began experimenting with Golden Open acrylics sometime in January of this year. My primary objective was to use them for plein air work. My main motivation in trying this specific variety of acrylic was that it walked in the boundary between regular acrylic and oil in terms of workability. I tend to have a habit of not being super happy with my plein air work and doing a range of tweaks to it in the studio ranging from just some very simple touch ups to full repaintings. I wanted to be able to make those tweaks while still on location by giving the painting some time to dry which is not remotely possible when using oils.
As you may remember, I started with just a small handful of colors to begin with. I chose colors that were frequent players on my palette and with which I was comfortable. However, I quickly noted some glaring differences in the way in which these colors played together. Firstly, I realized that these acrylics apply much more translucently than oils typically apply, very glazy. I think this is primarily due to the fact that these paints are pretty soft in body and go on pretty thinly. But my main issue dealt with the relative lack of depth I could achieve in the darks. I think a big part of this was that the red oxide I bought was inherently fairly opaque and so, when mixed with cobalt blue, it made an interesting earthy purple and not the deep dark typical of cobalt and transparent oxide red. I also noted that the Golden Open cobalt blue was lighter in value and more opaque than most standard cobalt blues in oil. It was a fascinating color, just not what I needed. Still, I made do the best I could and produced some passable paintings with that palette (some getting touched up in the studio with oil.)
However, before a backpacking trip that I was looking very forward to, I went to the LASS (Local Art Supply Shop) to see what all I could get to help out with this conundrum. I already had some colors in mind and hoped I would find them there. But during my perusal of the Golden Opens I noticed the Transparent Red Oxide (as opposed to merely "Red Oxide" which I had purchased) and I knew I had found one of the main reasons I was having trouble making nice deep darks. I was much happier with my results the next day as far as making nice darks.
So here is the list of colors I added:
Transparent Red Oxide