Traditionally, leadlight windows differ from stained glass windows principally in being less complex in design and employing simpler techniques of manufacture. Stained glass windows, such as those commonly found in churches, usually include design components that have been painted onto the glass and fired in a kiln before assembly. The extra time and cost employed in painting and firing the glass usually prohibited its use in domestic architecture. While stained glass windows are found principally in churches and ornate buildings, leadlight windows, which rarely employ painted components, are much more common, and from the 1860s to the 1930s were a regular architectural feature in many private houses and cottages, where their style is often a clue to the age of the building.
Unlike stained glass windows which are traditionally pictorial or of elaborate design, traditional leadlight windows are generally non-pictorial, containing geometric designs and formalised plant motifs. Leadlight windows almost always employ the use of quarries, pieces of glass cut into regular geometric shapes, sometimes square, rectangular or circular but most frequently diamond shaped, creating a "diaper" pattern.
A further difference between traditional stained glass and leadlight is that the former almost always has painted pictorial details over much of the glass, requiring separate firing after painting by the artist. In traditional leadlight this is not the case, painted quarries being separately produced and leaded in with those of plain glass, in the form of armorial crests and occasionally small scenes painted in grisaille (grey). Quarries painted in grisaille were employed both in the Medieval period and in the 19th century, the most famous ancient windows to have been decorated in this manner being in York Minster; these have inspired many 19th century imitations painted with little birds.