I have been reminded that some of the terms we throw around in the business may not mean much to the average person.
So allow me to clarify the studio terminology a bit:
Preservationencompasses the combined efforts and techniques of maintaining and protecting the integrity of stained glass. The approaches to preservation can be both conservative and restorative in nature. Much of this depends on the age, value, and historical nature of the window.
Among the techniques are repairs(where minor and unobtrusive),conservation (techniques saving as much original material as possible), restoration(reconstruction, partial or whole, of the stained glass using new lead and sometimes new glass and painted work to return a window to a “like new” condition), and protective glazing(additional components added to the exterior of the stained glass in various forms).
As in all artistic trades, there are (sometimes widely) varying opinions as to the merits of each preservation technique, and certainly no broad application instantly recommended for a particular window or church. After all, every edifice containing stained glass has a history, and most preservation efforts, in our experience, are driven by multiple factors.
In other words, every window is built with a purpose, but not all windows are built with the same levels of materials, craftsmanship, design intricacy, and artistry– and thus the drive to preserve them should be based on all of those things.