How do they color stained glass?

Elements of Color in Stained and Colored Glass

Cobalt, Gold, Lead, Copper and Uranium Have Been Used to Color Glass

Color is the most obvious property of a glass object. It can also be one of the most interesting and beautiful properties. Although color rarely defines the usefulness of a glass object it almost always defines its desirability. The Colored Glass Recipe: The earliest people who worked with glass had no control over its color. Then, through accident and experimentation glass makers learned that adding certain substances to the glass melt would produce spectacular colors in the finished product. Other substances were discovered that, when added to the melt, would remove color from the finished project. The Egyptians and the Romans both became expert at the production of colored glass. In the eighth century, an Arab chemist known as "Gerber" recorded dozens of formulas for the production of glass in specific colors. Gerber is often known as the "father of chemistry" and he realized that the oxides of metals were the key ingredients for coloring glass. The Glass Color Palette: Once the methods of colored glass production was discovered, an explosion of experimentation began. The goal was to find substances that would produce specific colors in the glass. Some of the earliest objects made from glass were small cups, bottles and ornaments. Religious organizations were among those who provided incentive to the early glass artisans. Stained glass windows became very popular additions to churches and mosques over 1000 years ago. These artists needed a full palette of colors to make a realistic stained glass scene. This search for a full palette fueled research and experimentation to produce a vast array of colors. Colors of Duration: Then, another problem was discovered. Many of the glass colors did not stand up to year-in, year-out exposure to the direct rays of the sun. The result was a stained glass scene of deteriorating beauty. Some colors darkened or changed over time, while others faded away. Research and experimentation continued in an effort to meet the need for colors of duration. Eventually a full palette of fairly stable colors was achieved. Metals Used to Color Glass: The recipe for producing colored glass usually involves the addion of a metal to the glass. This is often accomplished by adding some powdererd oxide, sulfide or other compound of that metal to the glass while it is molten. The table below lists some of the coloring agents of glass and the colors that they produce. Manganese dioxide and sodium nitrate are also listed. They are decoloring agents - materials that neutralize the coloring impact of impurities in the glass. Metals Used to Impart Color to Glass Cadmium Sulfide Yellow Gold Chloride Red Cobalt Oxide Blue-Violet Manganese Dioxide Purple Nickel Oxide Violet Sulfur Yellow-Amber Chromic Oxide Emerald Green Uranium Oxide Fluorescent Yellow, Green Iron Oxide Greens and Browns Selenium Oxide Reds Carbon Oxides Amber Brown Antimony Oxides White Copper Compounds Blue, Green, Red Tin Compounds White Lead Compounds Yellow Manganese Dioxide A "decoloring" agent Sodium Nitrate A "decoloring" agent Widely Known Glass Colors: Some colors of glass are widely known. Perhaps the best example of this is "cobalt blue" that is produced by adding cobalt oxice to the glass melt. "vaseline glass" is a fluorescent yellow-green glass that contains small amounts of uranium oxide. "Ruby gold" and "cranbery glass" are red glasses produced by the addition of gold. "Selenium ruby" is a red color caused by the addition of selenium oxide and "Egyptian blue" is produced by the addition of copper. Minerals: The Keys to Coloring Glass  The sources of the oxides, sulfides and other metals compounds used to color glass are minerals. The keys to beauty often come right from the Earth. Many thanks to Geology.com for this article!

http://geology.com/articles/color-in-glass.shtml

Choosing Glass Like the Pros

By Sara Peterson, from THE SCORE (#0071), published by Spectrum Glass Company

Is there a secret to glass selection? According to Roy Little, "color is everything." It's hard to argue with a statement like that—although when pressed, even Roy will tell you that, in the world of stained glass art, there's a bit more to it than that. When you look at the work of the incredibly talented team of Roy Little and Jim Raidl (Little/Raidl Design Studio, Cazadero, CA) there seem to be plenty of secrets they're not sharing. Their portfolio is packed full of an amazingly diverse range of projects that are rich in artistry and creativity. But what is truly remarkable is the way they can design a piece to fit so well into its surroundings. As many clients have observed, it often appears as though the piece actually belongs in the room or has always been a part of it.

We spent some time recently chatting with our old friends Roy and Jim trying to pry loose some of their closely guarded secrets. Roy, with his background in fine arts, is the designer of the team, while Jim tends to fabrication work and the important details of their thriving business. Jim and Roy are as much fun as they are talented. A conversation with them is an experience in its own right, but we did pin them down on a few glass selection areas that should be useful for anyone working with stained glass.

Roy's art background includes Trompe L'oeil—a very realistic style of painting. And true to that background, he selects glass very much like a painter chooses colors to add to his palette before approaching the canvas. Roy's first rule of glass selection is to only choose glass for one project at a time. When his pattern is complete and he has a clear idea of what he needs, Roy drives the 2 1/2 hours to his supplier and walks the glass aisles until he has his palette composed. Even if he happens to have several projects to gather glass for on the same trip, he walks those aisles separately for each one. That way, he can stay focused on collecting just the right shades for the effect he's creating in each project.

Rule number two: subtlety is a good thing. If Roy is spotted shopping for glass, he's frequently followed by a fan or two. More often than not, if one of these admirers has a comment about Roy's glass choices, it's that he has selected some ugly glass! That's because he works very hard at realism and, most often, that leads him away from the vivid, peacock colors toward the more gentle and subdued tones. Stained glass can be a very strong medium and unless there's a good reason to go for a big blast of color, Roy suggests resisting that temptation. When you look at the finished Little/Raidl creations, even the skeptics tailing Roy up to the checkout counter will agree, the glass is as stunning as the design. It all comes together perfectly in the hands of the master.

Roy also pays careful attention to the colors and "feel" of the surroundings where a piece will be installed. He picks up the flavors and tones used in furniture and other elements in the room and uses that information to design a look that becomes an integral part of the whole. He works closely with his clients, drawing out exactly what they are trying to achieve with the glasswork. He and Jim like to think of their clients as the artists and the two of them act as the medium through which the art is being expressed. It's amazingly effective and results in work that exists in complete harmony with its surroundings.

 

Roy did say that "color is everything" but he didn't really mean everything. While color choice is critical, in the world of stained glass there are many other things to consider as well. Glass can have unique characteristics—such as grain, texture, pattern, flow—that can be used to create some wonderful effects in a piece. A classic illustration of the use of a specific glass trait is the piece, "Whirligirl" that Jim and Roy created for us several years back. The carousel horse in Whirligirl is a study in Baroque™. The swirling patterns of the Baroque glass were carefully chosen to portray the roundness of the horse's cheek and chest and the flow of her cascading mane. The result couldn't have been more effective. Another way Roy has used a particular glass characteristic to its best advantage is in the waterfall pieces he has designed. In a single waterfall depiction, Roy has incorporated as many as16 different textures of clear glass to mimic what the eye would see as light refracts off a waterfall in nature. It's truly astounding.

Glass selection is every bit as important as the design of a piece. As you approach your next project, think of Roy Little. "Paint" the piece in your mind as you choose your glass. Really focus on that one project. Picture the room where it will be placed and choose glass to complement the other elements of that room. As you assemble your palette, always look for ways to use the unique characteristics of glass to enhance the effects of your work. And finally, consider Roy's advice: unless you have good reason to come on strong with color—subtlety can, indeed, be a very good thing!

Beginner glass cutting video from the Corning Museum of Glass

I thought I'd share a nice beginner video teaching how to cut glass from the Corning Museum of Glass.  It's especially helpful for people that want to start making fused glass jewelry and even stained glass windows but don't know how to cut glass!  In the video, the person scores the glass with the glass cutter while pulling it towards them, although I actually cut the opposite direction - away from me.  I find it much easier to see the pattern that I'm cutting if I cut forward.  If I pull the cutter towards me, my hand covers and hides the pattern piece that I want to cut! Click here to see the glass cutting video.  

Be sure to check out the Corning Museum webpage it is excellent.  They also have a lot of videos on YouTube as well.  

Nice, short video of creating a fused glass lamp

Today I thought I'd share this video from reflectionlabs.com on YouTube Fused glass sunflower lamp, it shows someone creating a fun fused glass sunflower ceiling lamp.  The video highlights how the artist cut out the glass shapes and prepared the piece before fusing.  What a great idea!   Many thanks to reflectionlabs for sharing this video.  
Fused glass sunflower lamp

Constructing a leaded glass panel

The Process in Overview

In this method a lead channel is used to hold the pieces of glass together as opposed to strips of copper foil "tape" in the Tiffany or Copper Foil Method. The lead came used is a soft, flexible material that bends easily to the shape of the glass. When seen in cross-section, flat came resembles the letter H laid on its side: It has a vertical crossbar down its middle, with 2 channels on either side. This crossbar, or heart, is approximately 1/16" thick and serves to separate the pieces of glass that are fitted into the channels on either side. The came is cut where it meets another came at intersections in the design. These intersections, called joints, are then soldered, front and back. When viewed a leaded piece appears as shapes of colored glass silhouetted and outlined by the dark came. The process of creating a leaded panel is sometimes referred to as glazing.

Lead Came
Lead is a unique metal: It is extremely soft in its pure form, has little mechanical strength, almost no elasticity, and melts at relatively low temperatures. These properties were probably the reasons early stained glass craftsman selected this it. They could form it into usable strips, it was easily cut, and easy to shape and work with their hands.

Why is it called lead came? The Romans were key in introducing the use of lead throughout Europe and the Mediterranean. They produced lead "came" by laying reeds side by side in a shallow pit. Molten lead was then poured into the pit covering the reeds. Once the lead cooled, it was sliced into strips and the burnt reeds removed leaving a concave channels for the glass. It was called Calamus Plumbum, or Reed Lead. As  Roman influence gave way to the Gaels in northern Britain, Calamus shortened to Caim. Later Caim was Anglicized to Came. This was how the channeled lead used in stained glass fabrication became Came Lead or lead came¹.

The lead cames used in stained glass are made by an extrusion process where the molten metal is pressed through a steel die, remember the Play-Doh Fun Factory?It can be pure lead or contain a small percentage of other metal alloys, antimony is one, to toughen or make it bright. You can also find in encased in a brass "skin" or made entirely of other metals such as copper, zinc and brass. Now it is even comes as lead free.

Lead came: All cames come in 4 basic shapes: round H, round U, flat H, and flat U. There are also specialty cames such as high heart and those with unique profiles like colonial and prairie style. The size if a came refers to the width of the face, regardless of style. 1/4" Flat U and 1/4" round H both are 1/4" wide. The portion that connects the two faces is called the heart and standard width is 1/16" and 5/32" tall. The channel is the portion the glass slides into and it is most often 3/32" deep. Lead is most often purchased in either 6 foot lengths or coiled on spools. Generally H cames are interior leads and U cames are used on the perimeter.

Safety First!
Lead is a potentially hazardous material and certain precautions should be followed to ensure safe handling. Lead and lead oxides are not normally absorbed into the body through unbroken skin. They can enter by ingestion or through an open cut. Detailed information is available from your lead came supplier, in publications from the SGAA but you can start with:

• Always wash your hands thoroughly with soap and water after working with lead.
• Never eat, drink, or smoke while working on your lead came projects. Keep all food and drink out of your work area.
• Always protect open cuts or sores with a bandage.
• Never allow children access to your tools, lead supplies or your glazing work area.
• Pregnant and nursing women must avoid contact with lead products.

In the Tool BoxThere are a few tools you will need unique to leaded glass construction. These are in addition to your basic glass cutting tools.

• A work surface that you can nail into and attached two raised edges (glazing blocks) to.
• Glazing hammer: special hammer with both soft and hard heads.
• Lead knife and / or lead nippers: for cutting the lead cames to length.
• Horseshoe or glazing blocks: for holding glass and came in place during construction and soldering.
• Lead pattern shears: These remove the correct amount of space from pattern pieces to account for the thickness the heart takes up.
• Fid: tool used to help fit, position, and seat the glass and lead during construction.

Preparation
Pattern Preparation: You will need to make 3 copies of your pattern. One for reference, one to cut apart with your lead pattern shears and one to assemble on. It is helpful to number and make any notations about color, grain direction on all three copies.

Work Surface Preparation: Lead panels are built out and down from a staring corner to the opposite corner. First attach two glazing blocks (strips of wood) at right angles to each other onto your work surface. These will give you and edge to work against and help keep your panel square as it is constructed. Place the working copy of your pattern with the bottom and left hand side against these two guides and secure in place. You will build your project on top of the pattern. This way you can check your piece size and lead placement as you go.

Cutting your pieces: Use your lead pattern shears to cut apart pattern piece copy. Use these to layout, score and break out all the glass pieces for your project. Check your piece size and shape by laying the cut pieces onto the assembly pattern. You should be able to see the drawing lines around each piece. Grind or re-cut pieces as needed.

Stretching the LeadLead came needs to be stretched just prior to use. This is done to remove the initial creep that lead will undergo in time and to also stiffens it. (For a more detailed explanation please read the Stretching Leadarticle by G. Copeland). There are several different ways to stretch lead: Two people can hold opposite ends in pliers and pull; you can secure on end in a vice and use pliers to pull the opposite or there are lead pullers. What you are looking for is to pull the lead straight back making sure no to twist or kink it. Initially you will feel some resistance, then the lead will give way and then you will feel resistance again.

Cutting the LeadUsing lead nippers requires just a bit of practice. You will cut across the open channel, not across the face. Cutting down through the face can cause the faces of the came to become smashed and distorted. You want to position the jaws at 90° to the open end of the lead channel, making sure the face of the pliers remains square to the came as you squeeze the handles and cut the lead to length. You don't want to tip forward or away as you cut. This will leave gaps in your lead joints and prevent them from soldering together properly.

You should notice that the side of the came that faced the flat side of the pliers has a nice, straight edge. The opposite edge on the remaining piece will have a pointed edge. This is due to the shape of the nippers. You will need to take your nippers and remove that point so that you have a nice straight edge before cutting it to length for you next piece. You also need to pay attention when cutting your came pieces to length that you are cutting the clean edge on the piece being used for assembly. Practice on some scrap pieces first to get a feel for the nippers and how they work.

AssemblyStart by cutting two pieces of lead for the bottom and left side edges of the panel. Generally U lead is used around the perimeter if the piece is going into a framework of some type. If you plan to free hang it you may want to consider using zinc or another metal U came for added strength. Place these on top of the working drawing, against the stops. Now place that piece of glass that goes into the corner, inserting it into the channels of both sides. You should see the drawing line exposed around the glass piece. If you don't remove the piece and either groze or grind it until it does.

Now take a piece of H came and measure and cut it to fit onto the exposed glass edge and butt neatly against the leading already in place. The place where two or more pieces of leading meet is the lead joint. Secure in place with a push pin or cushioned horseshoe nail. You will soon be able to gauge how much shorter to cut your lead piece to accommodate the channel overlap of the adjoining lead pieces. There may be places due to the design where the leads don't' meet at a nice right-angles and the leads need to be cut on an angle or miter to fit properly.

You continue building over and up in this manner, inserting the class pieces and fitting and cutting the lead came that surrounds them. This is where a fid and glazing hammer may be useful when helping fit and coax pieces into place. As you move along in the construction, make sure that your pieces are fitting within the lines of the design and you're sufficiently securing the pieces as you work to prevent shifting.

When all the glass pieces and interior leading are completed, use more of the perimeter came to finish the remaining edges and secure the entire panel in place.

SolderingLead projects are soldered at the places where lead cames meet, the joints. This is different from copper foil where all the seams are soldered together. The soldering tools needed are the same: a chisel tip soldering iron for stained glass, a stained glass solder, flux, and a well ventilated area to solder in. You may find a iron and rheostat combination easier to work.  It allows you to control the tip temperature so that you melt the solder and not the lead came. It is a good idea to tip test your iron before soldering. Hold the iron tip against a scrap of lead. You should be hold the iron there for a few seconds without melting the lead came itself. This is where an iron and rheostat combination is handy in helping you dial in the exact right temperature.

Apply flux to all the lead joints. The goal is to apply flux only to the you want the solder to stick to. A rule of thumb is that the solder extends out from the center of the joint an amount equal to the width of the came face. Place the end of the solder on the joint and touch it with the flat side of the iron tip and allow the solder to melt down onto the joint. At that point move the tip in a small circular motion for just a second then pull (not lift!) the tip away. The solder should flow into a gently rounded bead, extending evenly onto all the cames from the joint center. If the solder is not smooth, place your iron back on the soldered joint and move in a circular motion until it is molten then pull away. You may need to apply a bit of additional flux.

You will solder all the joints on the front of the panel then turn it over and repeat the process on the back. Inspect both sides to make sure you haven't missed any and you have nice, smoothly soldered joints. Clean and then you are ready for cementing, the final step.

Occasionally you may find a your leads don't exactly meet edge to edge and there is a gap. These gaps won't take solder and can prevent proper joining or result in a pinched solder joint. Beginners especially find this when the flip the panel over to solder the back. There is a way to bridge that gap called chinking. Chinking involves taking a small piece of came and cutting it half long-ways, down the center of the heart. You then cut small pieces from one of the halves that will fit into that gap snugly. Flux and solder as outlined above. You can find more information on soldering both lead came and copper foil products online in Inland Crafts' free How to Solder Like a Pro booklet.

CementingThis is the final step in assembly of a leaded glass panel. It helps secure the glass in the came, strengthen, and weatherproofs the piece. Even if you are hanging the piece indoors you need to cement for the added strength it adds to the piece. The process forces the cementing material into the spaces in the channel between the glass and came.

You will  need a cementing product specifically for leaded glass, whiting (or sawdust), two natural bristle brushes and several layers of newspaper to cover your work area. Follow the manufacturers directions for mixing the cement. Pour some cement onto the panel or pick some up on the end of one of the brushes. You want to push the cement up against the lead, forcing the cement under leaves and into the channels, making sure to work against all the faces.

Once you have worked in the cement, sprinkle the entire panel lightly with whiting. Whiting helps soak up the oils, dry the cement and clean up any excess. Use the second brush to scrub the entire panel surface. Work first in a circular motion, then parallel to the lead came until all excess cement is removed. The whiting will also help burnish and darken the lead while polishing and brightening the glass. The longer you work the whiting, the darker the lead becomes.

Once the front is cemented and cleaned, turn the panel over onto a clean layer of newspapers and repeat the process on the back side. Leave your panel to lay flat for 24 to 48 hours to allow the cement to set and start curing. Wile drying, you may notice places where the cement has oozed out. Use a pointed wood stick (sharpened dowel, craft stick cut at an angle, fid) to scrape along leads and perimeter of each glass piece to remove. You can find more detailed information on cementing a leaded glass panel online in Inland Crafts' free Cementing "How To" booklet.

Thank you to our friends at Inland for writing this tutorial.  http://www.inlandcraft.com/

Dalle de verre

The most successful and most widely accepted new technique in the world of stained glass today is dalle de verre, better known as faceted glass, which is set into epoxy or other material. Its process of production results in a mosaic-like approach of pure color effects that can be utilized in window openings or entire walls.

As John Gilbert Lloyd notes: "It returns to the primary function of stained glass to transform a wall from a solid unyielding object to a cascading, fluid mural of shimmering beauty. While the medieval craftsman, joining small pieces of glass with lead to make intricate designs, achieved the same effect for Gothic cathedrals, the earlier Byzantines transferred their mosaic patterns into colorful window designs."  Present day development of the technique stems directly from this beginning."

Thick colored glass was first used in a decorative way by Byzantine artists, instead of embedding the glass in stone, pierced the walls clear through and set it in as window lights. Arabic type examples can be found in Spain, apparently finding their way from North Africa with the Muslim Invasion. Although the actual glass is no longer in place, the feathery stonework grills that remain definitely indicate they must have been filled with colored glass.

Both Persians and Saracens in the Eastern Mediterranean area, where the glass industry was born, set crude glass into wood, stucco and stone frames. With these examples the Gothic tribes moving west used similar applications in stone mullions in France during the fifth and sixth centuries. Viollet-le-Duc says in Vitrail,  "In the East, things change but little and window screens of stucco and marble enclosing pieces of vari-colored glass which we find in monuments of the XIII or XIV centuries in Asia and even Egypt, must be the expression of a very ancient tradition whose cradle seems to have been Persia."

The Islamic law of prohibiting the use of human likenesses being depicted within the mosque, and simultaneously, the Christian practice of encouraging the use of figure likenesses of Christ -- the Apostles, angels and saints -- in all the decorative media of the church may have implemented the change to the thinner leaded glass medium.

The Middle Eastern antecedents of dalle de verre seem to have vanished for several hundreds of years, until the 1920s, when French glass artists, experimenting with various new architectural directions, revitalized the ancient techniques.

Early pioneers in the modern development of dalle de verre include Auguste Labouret and his collaborator Pierre Chaudiere. A prolific artist, Labouret studied at L'Ecole de Beaux Artsunder J. P. Laurens and created many windows for cathedrals, railroad terminals, department stores hotels and ships' dining rooms.

Labouret was born in St. Quentin, France and developed the dalle de verre technique in the early 30s while working on glass in historic monuments. The artist sought a combination of modern strength and durability with a depth of color found in old glass. The thickness, broken surface and cut edge gives dalle de verre its characteristically rich translucence. The negative matrix area that frames each pane of glass is visually much heavier than the lead in ordinary windows. This characteristic, as with the earlier Islamic pierced windows, enriches the color by creating a great contrasting brilliance. This juxtaposition of brilliant color and dark surrounds can be painstakingly achieved in flat leaded glass by elaborately painting or by a combination of etching and painting of flashed glass.

Dalle de verre lends itself best to direct and vigorous design. It is a broad medium that, generally, does not encourage copious detail. In the St. Christopher window that Labouret exhibited in the Pavilion du Vitrail in the Paris Exhibition of 1937, he demonstrated that it was not incompatible with figure work, delicate detail and even lettering.

A variety of forms could be seen at this 1937 Paris Exposition with the Egyptian Pavilion showing a typical Arabic style of glass pierced plaster encased windows in traditional patterns. This was supposed to be the real origin of faceted glass.

Variously called beton glass (beton glas), concrete glass or mosaic glass, the renewal started and by 1939 had crossed the Atlantic when a beton glass window was installed in the Chapel at the Shrine of St. Anne de Beaupre, Quebec, Canada. This was designed and fabricated by Auguste Labouret and is believed to be the first such panel in North America. In the same year, the French pavilion at the New York World's Fair featured the same "Magi" panel that had been completed in 1936.

"One of the Magi" is one of Labouret's later works (1936), showing a good example of size and contrast of the glass. Note particularly the individual blades of glass set together in undulating rows. This cutting effect could only be achieved by using a hammer. Notice the ornamenting on the garment itself, the flowers, sky and stars, and the glass rods used. Contrasting in size are the larger pieces in the garment and jewel box (note the treatment on the edging of the jewel box). The flesh seems to have been traced and a matted texture effects the shading somewhat differently from the effect in St. Hubert's work.

The English precis for the French article describing the window, "One Of The Magi", is "This stained glass window, exhibited in L'Illustration, illustrates a revolution which has taken place in the art of fashioning stained glass. It is the work of Labouret, who has evolved a daring new technique in the manipulation of translucent materials. His windows, indeed, carry us far from the traditional method of setting flat pieces of glass in leads in the manner that has been followed for centuries. By the use of thick slabs of glass which he sculptures, M. Labouret obtains a multiplicity of facets about which the lights play with a color and an intensity which suggest the fire of precious stones. It is impossible to deny the remarkable effects he achieves by means of this new method, and it is easy to imagine the wealth of decoration, which it may, in the future, confer on our churches and cathedrals. The several slabs of glass, it may, perhaps, be added, are held together with cement."  [Labouret's earliest work appeared in print in 1930 illustrating the steps of execution of the center section of the St. Hubert window. The complete window appeared in the Christmas, 1936 issue of L'Illustration.]

Also, in the 1937 Egyptian Catalogue from the Paris Exhibition, there is a window, "L'apprenti Sorcier" (Sorcerer's Apprentice) which stands the test of time very well. This is by Jean Gaudin and contains 16 panels with vignettes of the story running bottom to top. While there are indications of pate de verre influences, it is a stunning window by any standard. (Pate de verre is a cast sculptured window; all the surface details are sculpted in a mold then the hot glass is poured into it. All the cast pieces are then assembled using cement as a matrix. It is possible that dalle de verre and pate de verre developed simultaneously as they have similar surface treatments.)

It was not until the end of World War II that faceted glass use became more accepted, and even then, it was an evolutionary process. The pent-up demands for new buildings in the United States and Europe after the war proved a fertile ground for the material, which was relatively easy to fabricate, comparatively inexpensive yet produced windows of brilliant color.

But, as Lloyd states, "Not until the completion of Sacred Heart Chapel in Audincourt, France(1951_1955) did the full appreciation of the form strike home. This large installation has been billed as the finest in France with the windows completely dominating the atmosphere. It is a concert in color, rhythm and visual harmony."

By 1950, additional windows had been fabricated and installed by Labouret for the St. Anne de Beaupre in Quebec, Canada. The complete job called for over 200 windows of which he had completed and installed 30.

The work, St. Luke, from the circle window from the Basilica of St. Anne de Beaupre, Quebec, Canada, shows advancement of the dalle de verre concept. The cutting is sharper, giving a crisper look to the window; there is ample use of negative space. The stars in the background seem to have become Labouret's trademark. The small amount of trace-like material used to delineate the nose, mouth, and ear of St. Luke, as represented by a winged ox, are surface treatments which are no longer used in this medium.

As news of these windows spread, it wasn't very long before Henry Lee Willet of Philadelphia, who with several contemporaries, visited St. Anne to view them first hand. Willet remarked: "I was fascinated by the windows being installed; Labouret has developed an entirely new technique. He uses pieces of glass four to six inches thick which are held together by cement instead of lead. I thought the windows were the work of a young artist and commented to a priest at the shrine that it took youth to think of a new approach. When the priest told me that Labouret was 78 years old I realized the windows were even more amazing. Here is a man developing new techniques at an age when most men have retired." Willet was impressed both by the man and the work, so he immediately contacted Labouret and arranged for an exhibition of his work at the Philadelphia Art Alliance for the fall of 1950, which was reported in the December, 1950 Alliance Bulletin. The exhibition included colored renderings, full size cartoons and finished pieces of dalle de verre. It expressed first-hand the media and all its potential to the American stained glass profession.

Lloyd points out that, "American studios cautiously entered the field with a few minor commissions forthcoming. Then came the revolutionary First Presbyterian Church, Stamford, Connecticut."  Constructed in a form that resembled a gigantic fish, (although the architect claims this was not done consciously but rather for acoustical effects), it is said to be one of the most powerful modern churches in the world. Great walls of faceted glass designed and executed by Gabriel Loire of France literally saturated the interior with overpowering color. Controversy raged, as might be expected, but it led the way to new concepts and thinking in church design. The First Presbyterian Church, Stamford, CT provided the springboard for American studios to abandon traditional taboos and energetically make up for lost time.

The first American studio to design, fabricate, and install dalle de verre was that of Harold W. Cummings of San Francisco, California. The year was 1954 and the location was Belvedere, California for the St. Stephen's Episcopal Church. The media described as Vitrolith by Mr. Cummings was cast in concrete. The installation consisted of 12 nave windows approximately 17 by 144 inches in a vertical design with 72 smaller rectangular openings scattered in a starry-like clerestory.

Roger Darricarrere, a former pupil of Labouret joined Cummings on this project as a specialist familiar with the process. The design throughout is of an abstract nature consisting of soft tints of color accented by powerful bands of rich color. The glass was hammer cut as practiced by Labouret with the design boldly approached.

Among early prominent dalle de verre projects is architect Edo Belli's Moreau SeminaryChapel and Library designed by Father Anthony Lauck of the Notre Dame University Art Department and fabricated by Conrad Schmitt Studios. The monumental window walls admit a virtual lacework of colored light. The deeply recessed glass set in cement resembles a sculptured bas-relief of sparkling jewels.

Father Lauck describes the dalle de verre concept by saying: "Some materials have a more marked character about them than others. Among these is dalle de verre. Not only is it deeply translucent, but it transmits light in clear brilliant colors. The thickness gives more depth and intensity to its color. The unusual means of shaping it by chiseling adds to its character. Hammer cutting fractures the glass in uneven sizes with notched and somewhat jagged edges. Faceting the edges breaks up the surfaces with shell-like ripples and facets, which brings out forcefully the crystalline angular structure of the glass. Each broken facet transmits its own hue, catches a different angle of the sun's rays or the sky's brightness and brings a varied pattern of sparkling light into the window. It is precisely this unique and individual charm of slab glass that appeals to artists, connoisseurs and patrons alike -- and many priests and religions may be ranked among these."

The material used to glaze early dalle de verre was a Portland cement. In order to use this material properly, it was necessary to pour to a thickness of one to two inches on moderate sized panels and to a thicker size on large panels. The pieces of glass used to make a panel ranged from two to six inches in thickness; it called for a thick pour of cement to produce a panel properly. In addition, the weight per panel was considerable. Cement also requires that a wire armature be incorporated into the panel for reinforcement against breaking while the thickness of the pour required that the cement be adequately cured before moving. Curing panels (the process of letting the cement settle and harden properly), required additional wetting of the panels lest the cement dry out too quickly and crack. Finally, considerable clean up was involved once the cement was dry.

Moving a 500-pound panel up six frames of scaffolding for installation required a hearty crew of men and a crane. Proper placement and adhesion was needed to allow the panel to expand and contract within the installation frame to prevent breaking. A proper sash was also essential to receive the panel and the thickness and weight of the panel necessitated that it be a substantial one. It became apparent that Portland cement did not have adequate adhesion to the glass and it was not uncommon for the cement and the glass to separate. Water could seep through and around the panel. When the cement was cast several times thicker than the glass, various internal stresses could cause the glass to suffer fractures. There were problems, shortcomings and limitations in using cement. Since it had been used from the beginning, many windows were cast from it, but now some began to seek a better matrix.

The search for a better matrix took some interesting turns. Some studios experimented with additives to various types of Portland cement. About then, Sauereisen Acid resistant cement#54 surfaced. Apparently this material was formulated as a coating for surfaces that were exposed to various types of acids. Its use as a dalle de verre matrix was interesting. The cost was relatively low and it was a lot easier to use than the regular Portland cement. It cured in 24 hours and was lighter than regular cement. However, it did not have much strength and required a wire armature and larger panels. The recommended thickness of a pour on a moderate sized panel was one inch. It was only available in white and its use with dalle de verre was limited. Then, Robert R. Benes of St. Louis, Missouri, had a better idea.

Epoxy resin was initially formulated to serve as a lining for the oil pipeline divisions of Mobil Oil Company. By coating the inside surface of the pipe with epoxy, any fuels passing through the line received less friction and incurred less heat buildup. This required less force from a pump to move the material. Epoxy was being tried experimentally on many applications. Bob Benes, working with the Jacoby and Frei Studios in St. Louis, formulated a special blend of the material for trial in replacing cement in dalle de verre windows. Several panels were poured of various sizes and thicknesses as directed by Benes. These were subjected to tests for tensile strength, expansion, contraction, warpage, longevity and the like. The subsequent evaluations showed that epoxy was by far superior in all ways to cement. It required less time for preparation, mixing, pouring and cleanup. It required no type of armature. It had a similar rate of expansion and contraction as the glass. When poured to a three-quarter inch thickness, a panel of 12 square feet could be handled by two men with little fear of breaking. It could be seeded with all kinds of aggregate for surface treatment; it cured for handling in twenty-four hours and cured completely in five days. It came in many colors. It was a very durable, strong and waterproof product, with great adhesion to glass.

Epoxy was magic stuff and though the cost per gallon was relatively high, it was just what the craft had been looking for. Epoxy and dalle de verre were joined from that day on. Benes applied for a patent and began formulating and selling this material to American studios. He traveled extensively to demonstrate the proper methods of mixing and using the material. Special formulations were made for special situations and special colors were mixed. If a studio had a problem using cement or another's formulation, Benes always complied when called on for help.

Robert Benes traveled abroad and pioneered the use of dalle de verre set in epoxy to the masters of Europe who had always used cement. There were other formulators who soon began offering their product in competition. Some were terrible, some mediocre, but few were as good as Bob Benes' Benesco.


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