Windows: A Book About Stained & Painted Glass

In Short

This comprehensive work examines the craft and art of stained and painted glass from the twelfth through the seventeenth centuries across Europe. Lewis F. Day traces the evolution of window-making from early medieval mosaic work—where tiny, leaded jewel-like pieces predominated—to the painterly, translucent pictorial compositions of the Renaissance. Grounded in decades of hands-on experience and extensive European travel, Day explores how techniques shifted, how architectural forms shaped window design, and why the physical limitations of glass and leads dictate the true limits of the medium. It endures as an essential guide to reading and understanding ecclesiastical windows.

The Story

The book opens with a foundational thesis: glassmaking begins in pure craft and physical execution before it can aspire to fine art. In its earliest twelfth- and thirteenth-century forms, stained glass operates on the principle of mosaic work. Craftsmen view colored glass as a material as precious as gems, using lead lines to hold small, rich pieces together without obscuring them with heavy paint. White glass acts like crystal, while dark pot-metal glass gives the luminous impression of rubies, sapphires, and emeralds. Paint is applied sparingly, primarily in thin dark lines or subtle stippling to indicate essential details.

As architectural styles transition into the Decorated and Perpendicular Gothic eras, large multi-light windows divided by stone mullions demand new design strategies. Windows grow taller and wider, prompting the introduction of light-filled grisaille, elaborate canopy structures, and silver stain—a process allowing white glass to turn a brilliant golden yellow in the furnace. The artist gradually shifts from simply setting colored tiles to painting directly upon the glass, expanding the tonal range while trying to maintain the medium's inherent sparkle.

The high point of technical complexity arrives during the Renaissance, but this mastery introduces the seeds of decline. Fine painters from outside the craft—accustomed to canvas and fresco—are commissioned to design windows. Treating the glass surface like a flat canvas, these artists ignore the structural role of stone mullions and lead lines, attempting to recreate solid modeling, full atmospheric perspective, and heavy enameling. Day shows how these techniques obscure the glass, destroying its primary beauty: translucency and the play of light. Ultimately, the narrative closes by urging a return to genuine workmanlikeness, emphasizing that glass design thrives only when artists respect the boundaries, leading, and natural qualities of their material.

How It Unfolds

The glazier as jeweller In the earliest medieval windows, the craftsman treats pot-metal glass as a collection of precious gems. Lead lines bind small pieces together to create brilliant, intense mosaic windows with almost no paint applied to the surface.

The shift toward painting As the demand for lighter church interiors grows, craftsmen develop techniques like stippling, line drawing, and silver staining. These methods allow subtle modeling and golden accents without smothering the natural translucency of the glass.

Architecture dictates design The evolution of Gothic stonework creates soaring windows split by stone mullions. Designers respond by developing canopy frameworks and grouping subjects across multiple lights to harmonize with the surrounding stone architecture.

The influx of external masters During the Renaissance, famous outside painters design vast window pictures, pushing the limits of paint and enamel. While technically brilliant, these designs often ignore the structural role of leads and mullions, sacrificing sparkle for solid pictorial realism.

A call for structural integrity Reviewing centuries of European windows, the argument concludes that glass art reaches its highest expression when design serves the material. True mastery lies in balancing figure and ornament while respecting the physical reality of light and lead.

The People

The Early Glazier Driven by a reverence for raw material, the medieval glazier seeks to create windows that mirror the richness of set jewels. He works exclusively within the physical constraints of glass cutting and lead line construction, refusing to defile the material with heavy paint. By keeping paint minimal, he achieves an enduring sparkle that later centuries struggle to replicate.

The Renaissance Master Painter Represented by figures like the Flemish court painters trained in fine art traditions, this ambitious designer seeks to achieve complete pictorial freedom on glass. He wants to render dramatic perspective, solid figure modeling, and complex narrative scenes across multi-light windows. However, his lack of practical workshop experience leads him to treat the window as a flat canvas, ignoring mullions and applying heavy enamels that ultimately deaden the glass.

The Glass Painter Craftsman Positioned between the fine artist and the workshop, this skilled technician bears the responsibility of translating grand pictorial designs onto actual sheets of glass. He tries to preserve the luminosity of pot-metal and silver stain while executing the intricate line work, delicate shading, and complex leads demanded by external patrons.

In Its Own Voice

"A stained glass window is itself the best possible illustration of the difference it makes whether we look at a thing from this side or from that."

Setting up the central metaphor of his investigation, Day opens his preface by noting how the medium reveals its true brilliance only from within the sanctuary.

"We are workmen first and artists afterwards--perhaps."

In laying out his analytical framework, Day grounds all artistic achievement firmly in the mastery of practical craft and material technique.

"Solidity is just the one thing we can best dispense with in glass."

While evaluating delicate fifteenth-century English shading methods, Day highlights the primary quality that distinguishes stained glass from traditional oil painting.

What It's Really About

At its core, the book argues against the subordination of craft to fine art. It explores the tension between material limitations and creative ambition, questioning whether technical advancement always represents genuine artistic progress. Day insists that every medium possesses inherent qualities—in the case of glass, translucency, light transmission, and architectural integration—that must be honored. When artists attempt to force glass to mimic the opaque, solid qualities of oil painting, they strip the medium of its unique power. The work ultimately serves as an argument for decorative discipline, asserting that true beauty arises when design works in harmony with structural constraints rather than trying to shirk or hide them.

Why Read It Today

This work remains a masterclass in visual analysis for anyone interested in architecture, medieval history, or decorative arts. Day writes with the clear, direct voice of a practitioner who has spent decades examining windows across France, England, Germany, and Italy. Rather than overwhelming the reader with dry dates or obscure heraldic details, he teaches the eye how to see—explaining precisely how leads function, how silver stain transforms white glass, and how stone mullions alter spatial composition.

Readers should note that the text assumes a keen interest in design mechanics and architectural structure. Its language is detailed and technical regarding methods like abrading, plating, enamelling, and grisaille painting. However, the reward is an immense deepening of appreciation for historical craftsmanship. Reading it feels like walking through a quiet cathedral alongside an expert guide who points out exactly why one window glows like a cluster of rubies while another appears heavy and dull. It leaves you with a permanently sharpened set of eyes for every church or museum you enter.