If your tapes have been in a flood, here are a few things you should know about their condition:
- Short-term exposure to water does not destroy most magnetic tapes.
- Most tapes recovered from floods can be restored if treated promptly.
- Water, alone, cannot damage the magnetic recording on ferric oxide tapes (such as VHS tapes).
- Large to medium size tapes resist damage better than very small tapes.
- Most older, analog tapes resist damage better than newer tapes.
- Most modern digital tapes such as Mini-DV, acetate-based tapes (reel-to-reel audio tapes), and metal tapes (marked MP/ME) do not withstand long immersion in water—keep immersion time to a minimum
You should also know:
- The most damaging exposure involves salt water, sewage or chlorinated tap water.
- Tapes that are left damp for extended periods of time can develop fungal growth quite rapidly. Fungus will continue to grow on damp tapes and may cause serious damage.
- Incomplete or partial drying can also result in damaging fungal growth.
- Uneven drying or exposure to heat can cause tapes to deform. Drying can also cause tape to stick to itself or to the inside of the cassette.
Until clean, keep wet tapes at their initial level of wetness. Most magnetic tapes can remain wet for several days as long as water is cool and clean, however older tapes may not survive longer-term immersion. Do not freeze wet tapes.
- If water has condensed inside a cassette, treat as a wet tape.
- It is not necessary to immerse tapes that are wet only on the outside of the tape pack.
- If tapes are already dry when you retrieve them from the flood site, it is best not to rinse or re-wet them. Most contaminants that are already dry do not represent an immediate danger to the tape.
Handle wet tapes very gently and NEVER attempt to play back wet tapes (this will cause irreversible damage). Water compromises the physical structure of magnetic tapes, making them much more susceptible to stretching, tearing, and edge damage.
To rinse off contaminants, be gentle and use only cool distilled water. NEVER rinse tapes with tap water that might contain chlorine.
- The most common and dangerous contaminants in water are salt, chlorine, and sewage.
Contaminants, especially sewage, may require special health precautions. Follow advice of your local health officials. Protective gloves/clothing must be worn at all times when handling contaminated tapes.
- Initial decontamination/rinsing should be done with the tapes still on their reels or in their cassettes to avoid damage.
- Do not touch magnetic media with bare hands.
- Do not unwind or remove tapes from the reel.
- Rinse tapes by gently pouring distilled water over the tape or by submerging the tape in distilled water and gently moving the tape from side to side.
- Try to keep labels on tapes to identify content. Water soluble labels may be damaged.
Stand tape on edge to dry, do not lie flat. Air dry tapes in cool, dry air within 48 hours.
- Never use heat to dry tapes. Heat can cause distortion and can accelerate damaging chemical reactions.
- Use fans to keep air moving without blowing directly on the items.
After drying and cleaning, copy the tape to a digital format.