The conditions of the environment are critical in that they do not vary. The temperature and humidity range listed above are guidelines on what the room should be. The recommendation is whatever the temp and humidity is, it should not vary more than +/- 2ºC or +/-3.5ºF and +/-5% humidity. It is the stable environment that is the key to longevity. Heat and high humidity can cause the tape to absorb moisture from the air (hydrolysis), that can cause the “sticky shed” syndrome some formulas have had in the past. The fluctuation of temperature will cause the tape to expand and contract on the reel or hub causing uneven winding and possible cinching of the tape. The uneven tension of the tape can also lead to edge damage and “cupping”, which is the edge of the tape is not flat compared to the middle and the edge rises above the head during playback. Once the edge is damaged it is very difficult to recover the information from the reel. It is also recommended that the tapes be rewound and then played every 2 to 3 years to exercise them and then store them again.
The tape must also be kept away from magnetic fields, such as electric motors, lights, transformers, power supplies, etc. It does take a magnetic field of twice the coercivity of the tape to affect the recorded information, but some appliances such as a vacuum cleaner can have a field that is strong enough. Needless to say, don’t put tape in a carpeted room and have the cleaning crew come in and vacuum the room. Many of the tapes stored on the bottom shelves may be affected. Weak magnetic fields can cause an increase in print through, large fields and erase the tape.
The reels should also be stored in the tails out condition. This will give the reel a smooth tape pack and even tension across the length of the reel. If the tape is rewound and then stored, you will have uneven tension and possible leafed layers. The reels should be store in the vertical position so the tape is supported by the center hub in the box. Do not lay the reel horizontally as this will put pressure on one edge of the tape and can cause deformation of the edge.
Boxes and any labels attached to the boxes should be made from acid free paper. Acids, which are found in some packaging can act as a catalyst in the chemical breakdown of the magnetic tape when in close proximity to tape over long periods of time. The result can be crystallization of the lubricant or hydrolysis.
Before use, the tape should be acclimatized for a few hours if the temperature of the tape archive deviates by more than ±5°C (±9°F) or its relative humidity by more than ±10% from the conditions in the studio.
Keep all parts of the tape drive mechanism that come into contact with the tape free of debris and other contaminants. All parts of the machine that come into contact with the tape should be cleaned with a suitable cleaning agent (e.g., methyl alcohol) at least once a day.
The tape tension of the machine must correspond to the manufacturer’s prescribed values. A regular check is recommended not just to keep head wear as low as possible, but also to achieve the most careful treatment of the tape possible. Winding the tape too tightly causes deformation of the magnetic coating by the matt back coating and indentations by foreign objects that are wound into the tape. Winding the tape too loosely leads to slipping of individual windings (cinching) and creation of folds and creases when tape is accelerated.
Sweat from the finger contains salts, fats and other chemicals that can damage the tape. For that reason, touching the tape with bare fingers should be avoided.
Never press the reel flanges together. Replace any flanges that are bent. To prevent edge damage the tape should never rub against either flange.