Look for chemical deterioration of historic tapes with a substrate of cellulose acetate (produced until 1970's):
Identification of cellulose acetate tapes:
Brown or bay colour, rarely black. Tape pack translucent when back-lit. Tape breaks easily with nearly straight edges
Typical deformations are caused by:
- Different elongation and stretching properties of the components
- Hygroscopic tape
components
- Vinegar syndrome
- Brittleness
- Deformation ("spoking", "cupping")
- Cracks
Acetate deformation / cupping
Acetate deformation / spoking effect
Acetate deformation /spoking effect