The coloured print was badly stained by acidity from poor framing materials interacting with sunlight.

Treatment

The print was washed and buffered to reduce the acidity and to raise the PH.
Chemical stain removal was carried out over a period of several days. 
The print was washed remove the chemicals.
The print  buffered to raise the PH, to protect from acidity during display.
The print was pressed and dried.
The print was mounted with archival hinges using a archival adhesive on archival mount board with a buffered coloured over mount.