Types of Enclosures

All volumes books from the Book Hospital are placed in cases to preserve them and minimize any further deterioration. There are four types of cases: Prefabricated cases (prefabs), CMI cases, phase boxes, and Tyvek envelopes. View more information on enclosures on the Books End-Processing Manual.

• Prefabricated cases, called prefabs for short, are archival pre-made cases purchased from a vendor with stiff covers, cloth spines, and inner pockets.
• CMI cases are manufactured by a vendor (Custom Manufacturing, Inc.) that creates custom archival clamshell cases easily assembled when delivered to Houghton Library. They are made of archival corrugated tan board that completely encloses the volumes.
• Phase boxes are cases produced at Widener Library’s Preservation Services. They are custom, extra sturdy, archival blue boxes with string tie closures. They are only used for vellum-bound volumes and other special circumstances.
• Tyvek envelopes are usually used for books not needing preservation but . Generally, these books are part of a multi-volume title where one or more books were in the Book Hospital.

Enclosures Assessment

Each book is assessed for the case that best meets its preservation needs. There are some general rules to assess the appropriate casing needed. Additional information is available in the Books End-Processing Manual.

• Prefabs cases are used for books that securely fit in the inner pockets. These books usually measure less than ½ inch in depth. Guides on the inner pockets are folded to create a case-like environment. All appropriately sized books, except for vellum books, are placed in prefabs as a first resort.
• CMI cases are used for the majority of the Book Hospital books, except vellum books.
• Phase boxes are reserved for vellum-bound and other special books only. Vellum-bound books are only cased with phase boxes, no matter their depths. When a book has metal parts anywhere on the cover (metal adornments, metal clasp, etc.), it automatically is fitted for a phase box. If there is a question on whether a book has a vellum cover or not, consult the Technical Services Librarian.

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In addition, some volumes in the regular stacks are sent to the Harvard Depository. When a multi-volume title in the Book Hospital has other volumes in the regular stacks, they are pulled and processed and sent to the Harvard Depository to keep the sets set together. The only exception to this rule is when a volume set has two or more copies at Houghton Library. When that occurs, it is appropriate to break up the set. There are exceptions, however. Speak with the Technical Services Librarian to discuss any issues with multi-volume sets.

When regular stacks volumes are sent to the Harvard Depository, they are not placed in cases unless their condition warrants it. Usually, they are placed in Tyvek envelopes used for non-Book Hospital volumes books and tied with the approved string. They are processed with barcodes and spine labels just as their companion volumes are.