A facsimile is a copy of a specific volume or book in which every single detail is meticulously reproduced as faithfully as possible. Unlike anastatic prints, facsimiles not only replicate the text but also all the material features of the book as an object, such as the dimensions of the pages, the weight of the paper, the colour range of the decorations, the bookbinding materials, and other precious elements, so that they are identical to those used in the original book. This process also involves reproducing all the book’s defects (e.g., woodworm, traces of humidity, signs of use, impurities, and missing parts) as they form the hallmarks of its history. The book is bound using traditional methods and materials that are similar to those used originally to create a replica of the original text. A facsimile is only considered as such if it fulfils all these requirements rather than those of other forms of reproduction, such as anastatic printing.
In almost all cases, the reproduced books are handcrafted medieval or Renaissance illuminated manuscripts.
The facsimiles are accompanied by a volume of commentaries, containing historical and artistic studies about the reproduced book and, sometimes, a translation of the text. The publisher undertakes to guarantee not only the integrity of the facsimile and its faithfulness to the original but also certifies a limited number of copies of each volume (under a thousand unique copies that cannot be reprinted).
The process of producing an “almost original” involves a range of traditional techniques used by the copyists and bookbinders of the Middle Ages in conjunction with modern techniques using the latest technology.
A high-precision camera is used to take photographs of the manuscript. The photographs are printed on extremely sensitive photographic plates which capture all the different nuances of colour in the pages of the original book. The images can also be captured using digital cameras to avoid the posterior process.
The plates are superimposed on a cylindrical scanner that identifies the colors in the image and synthesizes them using the four basic colors (magenta, cyan, yellow and black). In this process, the initial chromatic adjustments are made by a computer that adapts the shades of color to specific preset parameters. The first print, as with the entire production process, is printed on traditionally handcrafted paper that replicates the texture of parchment.
So that the facsimile is as faithful as possible to the original document, the test print is compared with the original codex on a 5,500-degree Kelvin photographic light table. Each shade of color and detail of the base paper undergoes careful inspection and comparison, respecting any imperfections or deterioration incurred by the original text over the years.
To print the facsimile, the definitive photolith films that most closely resemble the original pigments are selected. The pages are combined into booklets of eight, sixteen or more pages. Some documents are printed separately and later attached by hand to the final book.
Silk-screen printing and engraving techniques are used for illuminated texts that contain paints with metals, such as codices and other books copied in monasteries. Miniatures of ancient manuscripts were typically decorated with liquid gold, gold pigments, gold leaf, and burnished gold. To replicate these ornaments, a sheet of copper is embossed to reproduce the parts that were encrusted with metal. A thin sheet of gold or silver is placed between the plate and the page. Then, pressure and heat are applied, and the metal sheet adheres to the paper.
This is an artisan process, just like that employed in the Middle Ages. The hand-folded booklets are put into order, reinforced with a printing press, and hung on a loom where they are handstitched. The binding must be identical to that of the original document.