|of similar paintings. I wanted to know whether it was possible to identify the 10 basic paintings featured on the PBS series. To do this, I ran a k-means clustering analysis of the paintings.3 The results were mixed.
First, let’s look at the clusters that make intuitive sense. The clear winners are:
· A cluster of 50 paintings tagged “snow” and “winter”
· A cluster of 28 paintings each with an oval white-space frame
· A cluster of 35 paintings of ocean scenes.
These were the kinds of clear clusterings we were hoping to find. Each has a common theme and falls under the banner of iconic Bob Ross images. He painted about one beach scene and one oval-framed image per season, and about two scenes with snow in the foreground per season. It makes sense.
Here are some clusters that also make sense, but don’t tell us a whole lot about Ross’s favorite kind of painting:
· A cluster of 13 paintings by guest host Steve Ross
· A cluster of 7 paintings containing a bridge
· A cluster of 11 paintings containing flowers
· A cluster of 30 paintings containing a fence or a barn
· A cluster of 33 paintings containing a waterfall.
These clusters identify some tags that appear in only a few paintings, but the groupings are not supremely helpful in defining what Ross painted. For example, flowers were very rarely the main focus of a painting, and we already knew how many times Steve Ross appeared on the program.
The final two clusters were the most broad:
· A cluster of 95 paintings that had trees and at least one mountain
· A cluster of 103 paintings that had trees but no mountains.
Not supremely helpful, but still quite interesting. Clustering analysis is an appealing tool for this kind of data but hardly has all the answers.
To learn more about Ross and his work beyond what I already knew from the data, I called Annette Kowalski, who founded Bob Ross Inc. with the painter and remains the steward of his work.4 She confirmed something I had discovered in my review of hundreds of Ross’s landscapes: His work isn’t defined by what is included in his paintings, but by what’s excluded.
“I can think of two times he painted people,” Kowalski said. “There was a man by a campfire,5 and two people walking through the woods.”6 Indeed, our data shows that Ross only painted a person — in silhouette against a tree near a campfire — one time.