If you are considering a stained glass commission — for a church, a public building, or new construction — this page is for you. It tells the story of how stained glass is actually made, and why I have spent nearly twenty years making art glass in Germany with one of the great glass studios in the world.
“The heart must submit itself courageously to life’s call without a hint of grief, a magic dwells in each beginning.” — Hermann Hesse
How It Began
When I was twenty years old I went to El Salvador to volunteer at an orphanage, in the middle of a civil war. I had a camera with me, and one day I took a photograph of the children eating lunch upstairs. The kids were seated at a long table in a way that reminded me of Da Vinci’s Last Supper. The child at the center held a gesture of Christ, with light pouring in from the window behind him. Looking back now, I can see I was already aware of how light changes everything — how it brings a kind of sacredness to a space.
My first work in glass was not stained glass — it was a solstice marker, a 450-pound block of precast concrete with an opening in the shape of a spiral and glass set into the wall. It was a State of Colorado commission, made in collaboration with Klipp Architects for the Center of Southwest Studies at Fort Lewis College in Durango, Colorado. I had been thinking about the play of light and shadow in the Southwest landscape — the way the ancient peoples of the region built solstice markers and lunar alignments into their architecture, the way even small structures carry these markers. At Hovenweep, the sun creates a dagger of light across three spirals on the cliff face at the summer solstice. I wanted to reverse that — to bring the sun back inside, to make the sun a return visit to the museum.
To get the alignment right I worked with astronomers, satellite engineers, and survey crews. And now, each summer at sunrise, sunlight enters the spiral and collimates a shaft of light across the Great Hall. The spiral appears on the opposite wall almost instantly, fully formed, as if a switch has been thrown. For ten or fifteen minutes it moves slowly across the wall, and then it is gone. People still come out each summer before dawn on the solstice to witness this event, more than twenty years later.
Years later, I was approached by architects to design clerestory windows for a major addition to a Lutheran church. The project never came to fruition, but in my research I contacted Barbara Derix, who was in the United States at the time. She took my call. She took me seriously. We spoke for an hour or more — and I only had that one prior glass commission. She didn’t need to give me that ind of time. Barbara understood immediately what I was saying about light and my design. She is brilliant, and generous in a way that has characterized every relationship I have had with that family. I thought: if I ever do get a glass commission, I want to work with Derix. It is one of the best decisions I have ever made.
Barbara taught me glass. She was my mentor, and I would not be where I am today without her guidance and generosity over all those years. She and her niece Anna have both visited us in Sioux Falls. Barbara visited my parents in Denver. That generosity has been present from the very first phone call.
The Studio and Its World
Founded in 1866, Derix is now in its fifth generation. This studio created stained glass for the two largest cathedrals in Europe. At any given time, artists from around the world are working there — each collaborating with a team of glass painters, cutters, acid etchers, airbrush artists, and restoration specialists, each of whom has spent a lifetime developing a single skill at the highest level. That depth of craft is what makes it possible for an artist to bring an idea into glass without compromise. You are not limited by what you can do alone. You are supported by what a team of people can do together, each one a master of their part of the process.
Wilhelm and Brigitta Derix, who together built so much of what Derix is, have since retired. Wilhelm believed that an artist should not limit the possibilities of their work through limited skills — that the studio existed to realize the nearly unlimited possibilities of an artist’s ideas in glass. That philosophy is still present in the studio today.
The studio is now led by Rainer Schmitt. Frederik Richter, with whom I have worked from the very beginning of my time at Derix, is still there. Anna, Barbara’s niece, is the person I work with most closely now — she is kind, patient, thorough, and so completely attuned to what I am trying to do that she takes care of everything. The family feeling of the studio has not changed. Brigitta cooked meals from her garden — whatever was in season — and the family dining table upstairs was where artists from around the world sat down together and talked. Conversations ranged widely — biking routes in France, the mythology of the American cowboy, the work being made downstairs, but at 1:00 pm sharp, Brigitta would say: now back to work.
Over the years I have come to understand, by being at Derix, the history of modern glass. I met Kim en Joong there — a Dominican priest and painter who was making completely abstract windows for what Wilhelm told me was the oldest Romanesque church in France. The combination of those ancient walls and gestural abstract brushstrokes is amazing — how naturally they belong together, how the one seems to call for the other. Johannes Schreiter was generous enough to meet with two different groups of my students over two separate January interim trips, and to look at their work. His relationship with Derix goes back more than sixty years.
One time at Derix, I watched Johannes Schreiter’s windows being fabricated for the Peterskirche — St. Peter’s Church — Heidelberg’s oldest church, which has served as the university chapel since the Middle Ages. On a later visit to Germany, it was a thrill to see those same windows installed in the church. German art historian Holger Brülls has written that no other living artist has embodied modern stained glass as Schreiter has — and to have known him, and to have watched that glass go into that church, felt like witnessing a piece of history.
The history of German glass — Ludwig Schaffrath, Georg Meistermann — created glass with Derix too. I was in Germany when Ludwig Schaffrath passed away, and I remember Barbara lamenting that history was passing too.
For a time, I was questioning whether I belonged in a place with such giants in glass. Then one day Johannes Schreiter looked at one of my windows I was working on and said — in German, which made it land differently — that the color was exactly right. After that, I felt like it was okay to be there in the studio.
My friend and fellow artist Yvelle Gabriel is a German glass artist whose life’s work has been shaped by reconciliation — a synagogue in Israel, a peace window in Poland, work recently presented to the Pope. He once told me that his own grandfather had been a Nazi. He carries that inheritance and answers it with beauty.
Yvelle and I went together to see the Chagall windows at St. Stephan in Mainz. It was fitting to be visiting this church with Yvelle — a place he knows well and returns to often. It was at St. Stephan that Chagall — a Jewish artist who had fled occupied France — agreed, after years of persuasion, to create windows in Germany as a symbol of Jewish-Christian reconciliation. He worked on them until his death in 1985. As Yvelle and I were about to leave the church, a small taxi pulled up. Yvelle said: wait, let’s see who gets out. It was Monsignor Klaus Mayer — the pastor who had spent decades persuading Chagall to come to Germany, the father of those windows — in his nineties, still coming to the church. He spoke with us briefly and kindly. To speak with the man who had made all of that possible made me feel just a bit closer to this amazing history of glass.
The People Who Make It Possible
The designing, drawing, and coordination with architects — all the way through construction documents — happens in my studio in Sioux Falls. The work is fabricated and realized at Derix. My collaborator there is master glass painter Olaf Hanweg. We have worked together for nearly twenty years. He knows how I think. He knows when to follow my design precisely and when to bring his own judgment.
Karl Heinz Traut, now retired, managed most of the projects I have done at Derix over the years and has traveled to the United States to help install the work. Erik Feltes has installed my windows on site, and Johanna Feltes has cut the glass on many of them — work that requires extraordinary precision and a deep reading of the design. Others from the studio have made the journey to the United States as well. For the dedication of Our Lady of the Angels, the Franciscan Renewal Center flew Olaf and his colleague Roman Olichowski — who painted and did much of the acid-etching on those windows — from Germany to Arizona to be present for the blessing. The studio does not simply make the windows and ship them. They see the work through to the wall, and sometimes beyond.
Several parish communities have sent leadership and committee members to Taunusstein during fabrication to see the work taking shape. I have twice brought my own students to make small windows at Derix during January interim terms. When you commission a window, you are entering a relationship, and you are welcome inside it.
There is a guest book at Derix that visiting artists have signed over the years. One entry, by the American artist William Cochran, is titled “Prayer for the Glassworkers” — written in 2007, it is a poem that ends with an image of swimming in a deep sky. His poem speaks to how special this place is, and how glass itself transports you. You understand it just by looking into a piece of glass — how the color can anoint your eyes with wonder.
The Glass — Lamberts Glashütte, Waldsassen, Germany
Glass begins as three earthly materials: silica sand, soda ash, and limestone. At Lamberts Glashütte in Waldsassen, Bavaria, the process starts the evening before the blowing, when the kilns are brought up to temperature and the metals that will color the glass are introduced to the melt. Color tests are pulled through the night to make sure the chemistry is right. By morning the glass is ready.
Lamberts works in four teams, and watching them is like watching a choreography — each person moving in relation to the others with a precision that comes from long practice. The glass begins as a small bubble (the parison) on the end of a blowpipe, blown into a balloon and constantly rotated by hand.
When it reaches a certain size it is handed off to another glassblower in the team, who enlarges it further into what is called a gather. The gather is then shaped in a marver trough as it is spun. If the marver trough can create some beautiful textures in the glass.
When the gather reaches the right size, the blowpipe end is knocked off, then it is heated again and the other end is literally cut off and a cylinder comes into existence.
When I was there, one woman on the floor made all the cuts — slicing each cooled cylinder vertically with quiet precision. In another furnace, a glassworker flattened each opened cylinder into a sheet with a wooden block on the end of a shaft, and the marks of that block remain in the finished glass.
So are the streaks of the making, the scoring, the air bubbles — all the evidence of human hands. That evidence is the beauty of the material. When the sun strikes an air bubble at the right angle, you can sometimes see a prismatic rainbow inside the glass itself.
The traditional method of Lamberts’ hand-blown flat glass production was recognized and awarded UNESCO Intangible World Cultural Heritage status in 2023. It is a process with roots going back a thousand years, and it is the only process that produces glass like this.
I have had the pleasure of knowing Christian Baierl, Lamberts’ Managing Director, through dinners and conferences over the years — he is good company and a genuine steward of what this studio is.
I work with Lamberts glass because I think quite simply it is the most beautiful material on the planet. The sublime and flashed nuances are exquisite and move from the realm of traditional craft into what I see as the threshold of greater mystery. I love the rainbow potential for color. The energy and movement, especially in the streaky flashed glass produced directly in the furnace, has been an ideal starting point for creating the structure in my glass designs. Twice I have had the good fortune to take my students to Germany to visit Lamberts and see the glass being produced.
The glass is called antique not because it is old but because it is made in the old way. Each sheet carries in it the breath and the hand of the person who made it. That is not a figure of speech. It is literally true, and it is why the material holds light the way it does.
The Process
Before any glass is painted, there is extensive preparation. We work through glass samples and color tests, client approvals, and full-scale cartoons. By the time the actual painting begins, the research has been done, many decisions have been made, and the direction is clear. This is a German studio — that rigor is part of what makes the work possible.
Sample panels of all areas will be created. Typically a 1:1 sample is sent to the client for approval as well.
Glass painting is a layered art — there is no fixed sequence that applies to every window. Each commission requires its own plan, a thinking-through of colors and techniques in layers. Vitreous enamels are often transparent and interact with everything beneath them — stain a field yellow, paint red over it, and you have orange. These are iterative, informed, and compounding decisions. Each choice opens some possibilities and closes others.
One of the most enjoyable parts of the entire process is choosing the glass. Sometimes I order specialty glass from Lamberts just for a particular project, but at Derix there are walls and walls of mouth-blown antique glass — colorful, jewel-like and luminous, to choose from. It’s like going to the candy store. You are choosing a local color for each area of the design — green in this section, blue in that one, pink there — building the color structure of the window before a single brushstroke has been made. Once the colors are chosen, all the shapes are cut before any painting begins.
Often, an early set of decisions involve silver stain. Silver nitrate mixed with earth is painted or airbrushed onto the glass, then fired in the kiln. The next morning you wipe away the dirt — and what remains is a deep amber yellow color that has flowed through the glass to stain it from within. There is something almost alchemical about this process. As Monsignor Buelt has written, this is an incarnation in miniature, the earthly material become luminous.
Flashed glass is made by blowing a thin layer of colored glass over a base of clear or lighter glass, creating two distinct layers. Acid etching is often used to reveal what lies beneath — the glass is immersed in hydrofluoric acid, which begins to remove the top layer of color, creating a range of tones from a single sheet. Some colors etch away in minutes, like certain blues; others take hours, like some of the reds. Sandblasting achieves its own effects — when applied from the back side of the glass, it creates a softer, more matte quality of surface that diffuses the light.
When the painting begins, it is Olaf’s hand that takes over. We put on some Max Richter or other music and get to work. Olaf enters his zone — and I let him do his thing, with an occasional finger pointed at something to make a suggestion. Not much more than that gesture is needed, especially when you are both wearing respirators. I have painted at times as well, but Olaf is the glass painter. I ask him to interpret my designs, not reproduce them — to bring his own judgment and energy to the work, with the spontaneity that makes the glass feel alive rather than executed. I bring my thinking in drawing and painting, in my own materials and my own hand, and he responds in his medium, as a glass painter who has understood what I am after.
Upon firing, vitreous enamels bond to the glass and become molecularly part of the material itself. The colors will not fade. Depending on the design, a glass panel may be fired several times, maybe up to five times maximum. With each firing the risk increases, as colors can shift in the kiln in ways that cannot always be predicted. But the multiple firings are necessary to achieve the nuance and layering I am after — building the surface layer by subtle layer, as in a watercolor.
The antique glass can be painted on one or both sides, and antique glass can be layered by laminating one piece on top of another to intensify the color — building up layers of depth that would be impossible to achieve any other way.
Once the antique glass pieces are painted and fired, there is the option of adding another layer of color by painting and firing the carrier panel of float glass as well — this has to happen before the lamination begins. The carrier glass itself is typically painted on one side only, as the entire laminated unit must pass through a commercial tempering process.
Laminating the antique glass to the carrier panel is a technique pioneered at Derix, and is as much a stylistic choice as a technical one. Without lead came, there are no black lines to interrupt the flow of shapes and imagery. Light moves through the work unbroken, continuous, alive. This gives a very contemporary feel to the stained glass — and a quality of light much closer to watercolor.
The finished panel meets architectural and building code requirements and can be built directly into an insulated glass unit, or used to create a third panel on the interior of the building alongside an existing insulated glass unit.
What Collaboration Actually Means
What collaboration actually means, at this level, is that the glass painter must understand not just what you drew but why — the feeling behind the mark, the quality of light you were after, the thing the image is trying to do in that space. You prepare your original art with that in mind. Helen McLean, an Irish artist working at Derix on a commission for St. Colmcille’s Church, had a fun story to tell about this and to be careful. She had left a small piece of masking tape residue on her original artwork. The painters translated it faithfully into the finished glass.
One of the things I have come to love about working with Olaf is watching how he approaches a difficult passage. He doesn’t rush. He stands with the image, sometimes for a long time, until he understands what it needs. For the Holy Spirit window at Gloria Dei, I had brought him a gestural, somewhat abstract image — a dove in motion, with a suggestion of flame. He stood in the studio looking at it. Then he walked outside and picked up a handful of rocks from the ground, laid them on the glass, and airbrushed around them for texture. Then he tore a t-shirt into strips and assembled a dove from the torn cloth to use as a stencil for the silver stain. A paper stencil would have left too harsh of a sharp edge. The torn fabric and irregular soft edges provided exactly the softness the image needed, suggesting the dove as the Spirit in motion.
In the studio, there are no creative guarantees. You wrestle with the image, sometimes for a long time. You have to be present. You have to pay attention. Over the course of a long collaboration, things happen that you don’t plan for and can’t forget. During the fabrication of another commission, the window of St. Michael fell from the viewing tower. Olaf caught it for a moment but could not hold on, and it fell and shattered. It was necessary to start over. At the end of the project, Olaf put the broken pieces back together and gave me the window as a gift. It seems fitting that the defender of the church would have fought a few battles and carried a few scars. Monsignor Buelt was present when the window fell, and he speaks of that moment as evidence of a spiritual battle.
Glass painting asks everything of the glass painters. It asks your attention — to every mark, every edge, every intention behind the image. It asks presence — the willingness to stand with a problem until the answer arrives, even if the answer is a handful of rocks and a torn shirt. And it asks an openness to what cannot be controlled — the firing that shifts in the kiln, the window that falls and shatters, the brokenness that becomes, in the end, a gift. That arc — from craft to spirit to grace — is what this collaboration has taught me.
Derix has been a place where my spirit is renewed in the presence of great artists, working intensely with color and energy and light. The windows that have come out of this relationship are more than I could have made alone — more, honestly, than I could have asked for. Looking into a piece of glass, you feel as though you are crossing a threshold of colored light into another world. Nearly twenty years of working together has felt like that.
What has come back to me, through all of it, is a gift I am still grateful for. The chance to bring beauty into spaces where people are already open — where the light through a window can stop you, lift you, open something you didn’t know needed opening. Work that consoles and transports. Work that makes the sacred feel present and alive. Work that, on the right morning, with the sun at the right angle, might just take your breath away. That is what I have hoped for, and what this collaboration has made possible.
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