For archival storage, what is the maximum retained thiosulfate in fixer solution?

The maximum retained thiosulfate in fixer solution for archival storage is 2 mg/cm². This standard is established to ensure the longevity and stability of radiographic films. Thiosulfate can lead to deterioration over time if present in excessive amounts, potentially causing image quality degradation and loss of archival integrity. By limiting the retained thiosulfate to this level, the risk of damaging the films is minimized, thereby extending their usable life. This guideline is crucial for facilities that need to store radiographic images safely for long periods, allowing for reliable future reference and record-keeping.