

Drawing from a palette of traditions and from an artistic background just as varied, Stephen Knapp set out to create a new form of art — and a unique way of understanding an artist’s creation.
“What I’m trying to do most of all here is challenge any traditional notion of perception,’’ he said in a video interview posted on the Juxtapoz magazine website. “What is it? Is it real? Is it not real? Does it matter?’’
Mr. Knapp, who was 70 when he died in Worcester Friday, several years after being diagnosed with prostate cancer, used specially treated pieces of glass that he mounted on walls and in metal braces to refract and reflect dazzling beams of color.
He called his work lightpaintings.
The ways artists depict and use light have always been part of the painting tradition, he noted in a Zone One Arts interview, but “the difference for me is that instead of using paint to capture light, I’m actually painting with light, taking it a giant step forward.’’
The result is “like a portal,’’ he told the Globe earlier this year for the Game Changers issue of the Sunday Magazine. “Light itself is spiritual.’’
His work is held in private collections and museums, and his commissions include corporate clients, too. Mr. Knapp’s lightpaintings adorn buildings such as the entrance to Gordon Library at Worcester Polytechnic Institute and Tampa City Hall in Florida.
Critics, fans, and art experts alike have danced as nimbly as Mr. Knapp’s beams of light in attempts to describe his work.
“The strength of Stephen Knapp’s work resides, in part, in how it defies description and amplifies experience,’’ Susan Stoops, former curator of contemporary art at the Worcester Art Museum, said in an assessment that Mr. Knapp posted on his website.
“Although it incorporates color, light, and space — elements common to painting, sculpture, and architectural installation — the work can never be defined simply by one or another of these practices,’’ Stoops continued. “Similarly, to identify it too closely with the material of glass is also inadequate. Rather, it is a uniquely hybrid form, which is truly more than the sum of its parts.’’
No less unique was the path Mr. Knapp took to settling on lightpaintings as his defining approach.
“He was a self-taught artist and he was very proud of that fact,’’ said his daughter, Sarah Damaske of State College, Pa.
“Because he was self-taught, he never thought, ‘Well, people don’t do that,’ ’’ she added. “Being self-taught expanded options for him.’’
It also opened avenues of fulfillment. “I still get goose bumps thinking about how lucky I am to be able to work in such an amazing medium,’’ he wrote in a brief essay posted on boredpanda.com.
To create lightpaintings, he used what is known as dichroic glass, in which “sheets of glass are coated with multiple layers of metallic oxides in a vacuum chamber,’’ he said in the Zone One Arts interview. “The resulting material transmits one color — wavelength — of light while reflecting the complementary color.’’
The glass, he added, “is then mounted to specially fabricated stainless steel brackets and this large selection of pieces becomes my palette. Using these pieces of glass, I physically manipulate the light on the wall or on panels, separating white light into pure color and painting with light.’’
The oldest of three siblings, Stephen A. Knapp was born and grew up in Worcester. His father, Walter, was a mechanical engineer, and his mother, the former Antoinette Jacobs, was a homemaker.
When Mr. Knapp was a boy, his father offered lessons that would inform his lightpaintings decades hence.
“He taught me to look at the lawn and see the grass,’’ Mr. Knapp told the Globe in 1978. “We would walk in the woods and he would point out the little things that a lot of people would miss, the details of nature.’’
After graduating from Worcester Academy in 1965, he attended Hamilton College in Clinton, N.Y., where he majored in history, minored in English, and graduated in 1969.
During his senior year he began dating Frances Nichols, who is known as Frankie. He rearranged his schedule so he could return each weekend to Worcester, where she lived and attended college. “I just thought he was a terrific person,’’ she recalled. “He was very kind, very funny, had a great smile, and we seemed to like the same things.’’
They also became partners in his artistic work when she took over managing his studio. They moved to Princeton in 2012, after living in Worcester most of their lives.
As a college student, Mr. Knapp had envisioned a different creative path. Using a borrowed Leica, he began taking photos, and even shot his classmates’ yearbook pictures his senior year. But after he and Frankie married in 1971, they moved for a year to Nova Scotia, where Mr. Knapp worked on a novel.
He also kept shooting photos, and upon returning to Worcester in the fall of 1972, his images sold, rather than his words. “He went with one mission and came back with another,’’ his daughter said of the Canada sojourn.
As Mr. Knapp made the rounds in Boston and across the state, persuading interior designers and architects to use his work, his presence was an asset. “My dad was an amazing person who loved to speak to everyone he met,’’ his daughter said. “His interest in them made them interested in him, and opened doors for him.’’
Mr. Knapp kept expanding his artistic range, too.
“Lightpaintings came about because I had done photography, I had done ceramics in Japan, I’ve carved marble in Italy, I’ve worked in steel and glass, I’ve done mosaics,’’ he said in the Juxtapoz video interview. “I’ve done all these different things. That nonstop creativity of experimentation is how I got here.’’
He added that “for me the fun of what I do with light is that there’s nothing in our visual memory that prepares us for what I’m doing.’’
As he moved from one discipline to another, often blending them with each new step, Mr. Knapp had the courage of his creativity as commissions offered new challenges. “He would sometimes tell me, ‘I’ve just told people I can do this. I’ve never done this before, but I’m sure I can,’ ’’ Frankie said. “He often was reinventing himself as he went along.’’
In addition to his wife and daughter, Mr. Knapp leaves his son, Jonathan of South Hadley; his sister, Cherie Olihovik of Millbury; his brother, Joel of Holden; and a grandchild.
Family and friends will gather to celebrate his life and work at 1 p.m. on Dec. 9 in First Unitarian Church in Worcester.
Using glass in his creations, Mr. Knapp said in the Zone One Arts interview, “allows me to manipulate and explore light and illusion, perception and dimension. I revel in the purity of the colors, their breathtaking richness, yet I am most drawn to the edges and the soft shadows that overlay a whisper of color and the borders that define space. It is here that mystery and depth and wonder can be found.’’
Bryan Marquard can be reached at bryan.marquard@globe.com.