A phase box is a custom-made enclosure that minimizes light and dust exposure to the object stored within it, and is a common tool used by archivists. Phase boxes take their name from their role as part of phased preservation — that is, they were meant to be a phase in the life of a book on the continuum from basic preservation to full conservation (should the volume merit such intervention).[1]

A completed phase box.

Changing archival practices, such as institutional budget cuts, resulted in the phase box becoming the final destination for many rare books. In combination with proper storage techniques, the practice ensures that no further damage is done to the books kept within the boxes, while stopping short of actively conserving or repairing any damage that had already occurred. Recently, the GLO Archives staff has undertaken a phase boxing project to protect some of the oldest records in the agency’s collection.

The Spanish Collection aisle of the Archives file vault, featuring red boxes containing folders of titles and other documents. Bound volumes rest on shelves further down the aisle.

The records of the Spanish Collection[2] include thousands of titles to land in Texas issued by the governments of Spain and Mexico, as well as bound volumes that cover Spanish land and water law. These important volumes, spanning from 1544–1869, offer historical context for Spain’s claim to sovereignty over American land.

While the title documents have long been flattened and stored in acid-free archival folders within sturdy archival boxes, the volumes were stored on shelves in the climate-controlled Archives file vault. Phase boxing these volumes was selected as the appropriate way to provide them greater protection and to ensure that they would endure long into the future.

The process for creating phase boxes is time consuming. From taking measurements to creating the boxes and attaching labels, it takes about 45 minutes per volume. It requires the use of specialized library equipment, which means, for the GLO Archives staff, working off-site.[3]

There are many guides online for creating phase boxes, which vary depending on the author’s personal preferences. Everyone has their own method but the final product is generally the same. Using one of these guides, we begin by taking measurements of the vertical length, horizontal length, and width of the book.

Precise measurements mean a phase box will create a tight fit, leaving the book within as little room to move around as possible.

The boxes start out as flat pieces of acid-free book board. Using the vertical and horizontal lengths, we then cut two strips of book board using an industrial cutter. Each strip will become the vertical and the horizontal enclosure. The strips are then measured and marked in pencil along where creases will be made to create each part of the box. The excess is cut.

This machine, a guillotine shear, was manufactured in Worcester, MA by John Jacques & Son around the turn of the last century.

Each strip gets four turns in the corner rounder. Rounding the corners makes the boxes look more aesthetically pleasing and makes the phase box less likely to catch on clothing.

A 1/4 inch corner rounder in action.

Using an industrial crimper, each strip is crimped in four places.

The blue color of this machine, a manual paper creaser, is near universal in large libraries across the country.

Once all the pieces have been cut, measured, and crimped, we take them back to the office for a fitting. If they fit, then the two pieces are glued together using a pH neutral adhesive. After weighted drying overnight, we attach hook-and-loop fastener buttons (better known commercially as Velcro) to the box so that it opens like a book.

The drying room for phase boxes under construction.

Finally, descriptive labels featuring the Mexican eagle, an iconic representation of the Spanish Collection, are created and affixed to each box.