The phase box is a standard conservation housing that provides physical and environmental protection. In June, TSLAC Conservation modified a phase box to approximate an original protective structure.
House Documents v.112, 58th Congress, 2nd Session, 1903-04 is a collection of soil maps published by the US Government Printing Office (GPO.) Rather than bind the maps into an atlas structure, GPO chose instead to box them as loose, folded leaves. Unique care was then taken to make the box look like a book:

The box’s outer wrapper was covered in brown sheep leather. Spine labels are consistent with the look of GPO bindings.
It seems likely that this unusual structure originally protected the folded maps on its top and bottom, but these components are now missing. The back, covered board is missing, as well.
These maps receive relatively light patron use, so it was acceptable to leave them folded and boxed rather than flattened in a folder. Though the quickest treatment would be simply creating a new box, a bit of extra planning and time allowed preservation of the original housing’s careful aesthetic design.
First, a new inner wrapper was constructed of lightweight cardstock. The list of maps was lifted from the original inner wrapper and adhered in the same position in the new structure. Then, an outer phase box was constructed and the covering boards adhered. A new back board was made and covered in toned Japanese tissue.

Existing and new boards are adhered to the flattened phase box. Here, the replacement board has not yet been toned to match the leather.
The result is a more robustly protective structure that retains the look and labeling of the original. This box better protects the maps inside and retains its unusual, carefully-designed appearance.