In 1981, Christopher Clarkson, while Conservation Officer at the Bodleian Library, designed a system of die-cut boxes, folders and shelf envelopes. Two Oriental and four modern sizes were added by Clarkson to complete the eleven storage formats required. Guard fascicules which complete the system are designed to fit three of the die-cut box sizes. Introductory pamphlets are available which discuss the protection system and the design of the die-cut envelope folders and boxes in detail. Long side opening to help insertion and extraction of fragile items.
Seams are at short sides, no seam runs across centre.
A blind border line indicates the largest format that can be placed in that particular envelope. A blind box marks placement of shelf-mark. Two thickness adjustments for items of 12 mm thickness to 19 mm thickness. The folders have H slots cut through them to allow a tape tie to be used if required. Based on this design, and also available, are the pHase 3 tm Folder Boxes which are made of heavier weight Premier boxboard and which take items up to 140 mm thick.