Magnetic tapes are made of three or four layers depending on the magnetic coating used:

• - Back coat layer (Optional)
• - Substrate Layer (Film)
• - Data-Recording Layer (Magnetic particle + Binder + Lubricant)
• - Protective Layer (For metal particle tape only)

Magnetic tape particles of the data-recording layer (Iron oxide particle tape, MP - Metal Particle tape or ME - Metal Evaporated tape) are held together with a binder coated on a film substrate. Lubricant and other agents may also be included in the data-recording coat layer. A back coat may also be added to control friction and static charges.

The lack of industry standards drove manufacturers to create their own testing procedures, methods and tools to measure the quality of their magnetic tapes. Added to the fact that testing operating conditions are often different from end user environments it makes customers choices very difficult even after serious product evaluations and comparisons.