Windows : a book about stained & painted glass (1909)
Day, Lewis F. (Lewis Foreman), 1845-1910 · London : B. T. Batsford · leaf 236
220 … fade into white, and then at their interstices have smaller diamond-shaped pieces of glass let in. Where a subject glazed in quarries is represented against a background of more elaborate plain glazing, there is difficulty in joining the two, except by means of a strong lead outline to the figures…
Glass painting and staining · Windows
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.