During the preservation and rehousing process of the Holtermann glass plate collection, the Collection Preservation team has occasionally come across a broken plate.
The broken plates are cleaned, and then rehoused in museum mount board sink mats. The sink mats hold the broken pieces safely and securely in place, but still allow viewing access. The sink mat and cover is then sandwiched and sealed together with an archival paper tape for storage. All materials used in this process including tapes and board pass the Photographic Activity Test (PAT) and will not adversely affect the glass plate negative.