Hi, Mark, You have received three great answers, with which I concur. The one exception that was noted was using the plastic bag where there is a risk of flood. A few years ago, I was given a tape that had been stored in a plastic bag in a "time capsule." The tape was moist. Water/vapor will diffuse through many plastics given enough time. It seems to me that the small risk of flood and the limited protection the plastic bag offers is not a good trade-off against the detriments of its use. I do return the plastic bag to clients, but the tape is on top of it, not in it. Interestingly, while one might worry about the acidic content of a run-of-the-mill tape box, I have anecdotal evidence that the "bad actor" in this equation (at least with acetate tape) is the tape and not the box. More than a decade ago (yikes!, has it been that long?), I posted this to my blog: http://richardhess.com/notes/2006/10/16/acetate-tape-buffered-by-cardboard-box/ (all-in-one-line) Cheers, Richard On 2017-12-13 12:06 AM, Mark Campbell wrote: > I have a question regarding dew point and open reel tape playback and subsequent vault storage. > > It is a given that playback of tapes will occur in temperature and humidity conditions that are far from ideal for tape storage...(ideal being something approaching 16 deg C and 30% RH and a good studio for playback is set to be comfortable for humans not tapes ---22 deg C and 60% RH) > > The problem thus arise: > > If after playback of a 10" master tape...I dutifully place in back in its plastic bag and then into its cardboard tape box ...in doing so...I have capture a bubble of air which surrounds the tape inside the bag which is at 'studio conditions" (60%RH) > > That tape (well bagged and boxed) goes to an hypothetical cold store at (8 degrees 30% RH) > > My question is...will the plastic bag hold that 'studio-air' around the tape...and cause dew formation? > > And if so... > > Would it be best not to use the plastic bag at all...and allow the tape to 'breath' in its cardboard tape box? > > I hope to hear from you soon. > > Mark Campbell > > > > -- Richard L. Hess email: [log in to unmask] Aurora, Ontario, Canada 647 479 2800 http://www.richardhess.com/tape/contact.htm Quality tape transfers -- even from hard-to-play tapes.