Opalescent Glass: milky in appearance, opaque to light, and seen as reflected light color. Light enters the glass and is dispersed from within the confines of the glass.
Cathedral Glass: Usually machine rolled. The rollers may have patterns that will emboss or make an impression on the glass resulting in a texture. Very even in thickness, with a wide range of good consistent color, less expensive than hand and mouth blown glass, and fairly easy to cut. This glass is made by melting and extruding it through rollers onto a lehr. A lehr is a moving belt that moves the glass through an annealing oven to disperse the heat evenly.
Hand Rolled Cathedral: hand rolled one sheet at a time on a steel plate.
Glue Chip Glass: this process involves a light over spray of sandblasting, then applying a layer of animal glue (hoof & horn). It is then baked until the glue shrinks and dries. As this happens, it pulls away sections of the glass resulting in a feathered pattern. This would be single-chip. Double-chip is the same process only with a second application, which results in a tighter pattern; more crystalline in appearance.
Opaque Glass: A flashed glass opal with a milky finish to the glass.
Cats Paw Glass: Has a mottled look. Hot glass is rolled over a cool cast iron plate and the sudden change of temperature causes it to immediately contract. This creates the ‘cats paw” texture.
Craquel Glass: This glass (antique) in it’s molten state, is quickly dipped in water. The outside is cooled. This result is the crackled effect that can be large or small, depending upon the manufacturer.
Reamy Glass: Imagine molten glass being stirred just before it suddenly cools. That’s the look you get. Awesome handmade appearance. It allows for a great amount of light to pass through.
Sheet Antique Glass: Does not mean antique as in old (100 or more years) It simply refers to the method. It’s a modified version on the 19th century technique.. Mostly, antique glass is blown into elongated cylinder type bubbles. As the glass is blown, it is rotated up & down . During this process it is purposely scratched by spikes on the inside walls. These marks are what result in the movement we so associate with antique glass. The ends of the cylinder are then cut off and its split lengthwise with a hot knife. It’s then flattened out to a flat sheet and run through an annealing oven. This removes stress and brittleness. Even color, thickness, and real easy to cut.
Full Antique Glass: Made much the same as sheet antique except the ends are pierced and fluted one end at a time, the bubble it derives from is smaller and the glass is generally uneven in thickness. You will notice a sheet of this glass range from very dark to very light on one sheet depending on it’s thickness.
Beveled Glass: A piece of glass (normally 1/4” - 3/16” thick) that has been cut to a desired shape, then about 1/2” of the outer perimeter is ground and polished to a beveled edge. This edge, on a good quality bevel, should be free from scratches, waves or any trace of the beveling process. This beveled edge reflects the light and results in a show of light play in a rainbow of colors.

Flashed Glass: Antique glass with a thin layer of a primary colored glass fused to the thicker base colored glass.

RELEVANT GLASS TERMS:
Came: Strips of lead milled to specific shapes and sizes used to hold pieces of glass together.
Lead Joint: intersection of two or more pieces of lead during assembly
Leading: the process of joining cut pieces of glass together with lead came and soldering
Flux: chemical applied to the leaded joints or copper foil to allow bonding of solder. Solder will not stick without flux.
Solder: Combination of tin & lead (solid core) wire. Can also be a verb when meaning to solder.
Tack Solder: to add a small amount of solder to hold in place prior to full application
Tinning: to coat the copper tip of the soldering iron
Score: to cut or scratch the surface of the glass with a glass cutter
Grozing: To nibble small pieces of glass by hand with grozing pliers
Re-Bar: reinforcement strips soldered to the back side of a finished piece to add strength and prevent sagging and bowing over time.
Cementing: waterproofing process used in leaded panels to allow exposure to the elements as well as add strength and longevity to the finished piece.
Whiting: powdered calcium carbonate used to clean flux residue and clean the piece after cementing. Absorbs excess linseed oil and turpentine seeping from cement.
Patina: chemical process of various techniques used to darken or color the lead, zinc & solder. Also, can be the natural process that will occur with aging.
Carborundum Stone: an abrasive stone used to smooth the rough edges of glass.
Cartoon: Working drawing
Color Intensity: the degree of purity or brilliance of a color
Color Value: The relationship of color to lightness or darkness
Hue: color
Mosaic: an organized arrangement of smaller pieces grouped together to form a specific expression
Sandblast: the act of obscuring glass by forcing a stream of sand or abrasive grit through a nozzle under air pressure.
Restoration: the act of re-establishing the legibility, integrity or intention of the object.

ASSESSING VALUES AND RESTORATION REQUIREMENTS IN OLDER WINDOWS:
There were a huge amount of decorative windows manufactured around the turn of the century. There are alot of these still available for purchase. Some are really worth alot of money. Some are not. It would be wise to know a few things to look for that might authenticate your purchase. Stained glass windows today are easily produced to look as an old window would. There are many glass reproductions of both color and texture that are almost undetectable, even to an experienced glass artist. There are chemicals that promotes oxidation that will age a panel in appearance. If you are looking to purchase an authentic antique stained glass piece, evaluate the following:
Lead deteriorates from the inside out. The lead will be weak and brittle in most cases. If it is lead, you will be able to mar the surface with your fingernail. If you can scratch the color (dark gray/black) off the lead, there is a good chance it is new and you are removing the patina. This would leave a shiny silver mark. The solder joints in an old piece would not be shiny silver, even if clean. If the piece is installed in a wood sash it will probably be caulked around the perimeter with a compound similar to Dap. Chances are very good that the lead beneath this caulk is deteriorated beyond repair. A new zinc border will need to be added and soldered to the existing lead. Soldering old lead is not an easy task. If it has a well preserved zinc border, the caulking looks good and is not falling out, chances are, it is not old. It may be new or may have been restored. Look for signs of wear. Build-up of grease and dirt, crevices in the glass texture that are holding deposits of grime and multiple colors of paint splatters on the glass usually give clues to it’s past. Finding lead with ridges running the length of the lead is a good find if it’s in good shape. This would mean the lead was hand cranked and rolled leaving the impression of the crank. Glass breakage in older windows is common. Finding one in perfect shape is rare. Expect to make a few alterations.
Small cracks in singular lines running edge to edge are probably not going to do much more. A multiple shatter will eventually fall out. If the crack is not severe I would leave it. Missing glass pieces will need to be matched and replaced. If there are multiple pieces missing, the value as an old piece is not that good. In my opinion if the piece appeals to you, it’s worth it.
Restoring a stained glass window is the act of re-establishing the legibility, integrity or intention of the object. It is not necessarily returning the object to its state when new. Restoration may involve replacement of deteriorated such as the lead or zinc, repair of deteriorated elements such as the glass, redesign of structural elements to alleviate bowing or sagging, and waterproofing, also referred to as cementing. The cementing process a critical step in a well made stained glass window and protects them from the elements that do the most harm, wind and rain. It adds necessary rigidity to the window partnered with reinforcement bars. The composition contents of the cement and the correct application of this have much to do with the longevity of the window. The cement must adhere to both the glass and the lead or channels in which it was constructed. This adhesion must withstand the elements of water, heat and cold. The cement must be able to remain somewhat flexible to allow the window to slightly move with wind pressure and allow for expansion and contraction. A professionally cemented window, exposed to the elements, should be able to perform as intended for 75 to 100 years before needing reapplication.

 

TRADITIONAL COLOR RELEVANCE IN RELIGIOUS STAINED GLASS:
Colors in religious windows have specific meaning.
It is important to select the correct color to convey your idea.
• PURPLE- A sign of royalty. God the Father. A symbol of suffering & endurance.
• VIOLET- Love, truth, passion, suffering
• WHITE- Innocence & purity. The hue of God.
• PALE GREEN- The hue of Baptism
• GREEN- Faith. Spring. Triumph of life over death.                                              
• PALE BLUE- Peace. Christian prudence.
• BLUE- Hope. Love of divine works. Sincerity.
• GOLD & YELLOW- Power & Glory.The gates of heaven. Halo of the saints.
• RED- The blood of Christ.
• GRAY- Emblem of Christ risen. The darkness of sin & death.
• BLACK- Death & Regeneration

 

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