"It was one of the best things I ever did," Martindale said of taking the class.
Richard Diehl, 77, of Brooklyn Park, took the class after hearing about it from his sister.
He said he had experience painting with acrylic paints but not watercolor, which he said is more difficult.
Still Diehl painted two pictures he felt were worthy of sending to his aunt in West Virginia.
The first was a painting of northern cardinals, the state bird of West Virginia, and the other a portrait of his aunt.
"I would never have done that if he didn't show me how to do it," Diehl said of Stephen Crooks. "He pulls the talent right out of you."
Stephen Crooks has experience but most of it involved teaching children.
For a half dozen years, in the 1970s and 1980s, he taught art to elementary school-aged students at a private church school in Elkridge called Faith Bible Church Academy.
For a number of summers, dating back 35 years, Stephen Crooks and his wife have served as counselors at an art camp in upstate New York for young artists ages 7 to 15, he said.
They went back again this summer, he said.
Teaching young artists is much different from instructing members of the senior center, he said.
"I think what I found, was that the older students, and when I say older I say that very respectfully, is they were more attentive and cooperative in terms of sitting still," he said with a laugh.
"The best part of teaching, I think, is the contact you have with the individual, regardless of their age," he said.
"And seeing the spark in their eye when they understand something or experience something and realize this is something I'm really interested in doing," he said.