The book is 12mo of six leaves in a gathering. Some gatherings appear to have 7 leaves creating irregularities. This is due to the fact that illustration pages have been added to the gatherings after the sheet have been gathered.
Why does this happen?
During the early days, woodcuts which were published among the type were more popular. In the late sixteenth century, engraved type which is printed separate from type became more common method. Copperplate was often used for producing finest works of illustrations. “Plates for insertion in a book as separate leaves were added when the sheets were gathered in the warehouse” (Gaskell).
Change in the concept of book illustration
In the beginning, type and illustration were “printed off a single block”, creating a unique art form.According to Blomfield who wrote the article Book Illustration and Book Decoration, only after printer sought to utilize illustration rather than see it as an art form, illustration ceased to be art. The relationship between printers and artists ruptured as artists always cherish their works whether it is illustration or oil painting. “Illustrators made his drawings without thought of the type, and left it to the printer to pitch it into the text, and reproduce it as best he could. “