1 mil 1/2" Tape Question

[astrotoy]

Anyone with experience with 1 mil 1/2" tape. I recently bought a collection which has quite a few 1/2" tapes.  A fair number have 1 mil tape, or tape that is definitely thinner than the standard 1.5mil.  I haven't seen any 1 mil 1/2" tape for sale, new or used.  One tape has 69 minutes of music (at 15ips measured with the counter on my new ATR-102). The reel is quite full, but still with a little room.  According to my calculations, it has about 5200' of tape on the 10.5" reel. That doesn't seem possible.  For comparison it would be like having 3460' of standard 1.5mil tape on a 10.5" reel (or 46 minutes worth at 15ips).  Maybe the tape is even thinner. 

On the box there is a notation that says SM Uher while regular tapes say SM 911.

Playing it back, the sonics are great - no audible print through.

Thanks, Larry   

[docb]

That would pretty much have to be .75 mil tape.

[astrotoy]

Thanks, Dan.  Never heard of .75mil tape before.  I remember a long time ago there was .5mil tape.  Very difficult to work with - would stretch very easily.    Larry

[docb]

I dunno, it's a puzzle. Uher SM does not come up for me. I can only find one reference to Uher branded tape, called Z817, and it's a 1/4" 1 mil reel. And I can only find one Uher deck that could use a 10.5" reel, the SG530L, which appears to have been a 1/4" deck. And of course SM911 is 1.5 mil.

I did find an interesting mention of .75 and .5 mil 1/2" tape being developed for video use back in the 70s, in an old scan from Billboard magazine. So it's not impossible that such a beast could exist. Also it looks like BASF 931 was available in 5000 ft. 10.5" reels.

http://www.ebay.com/itm/1-REEL-BASF-931-DIGITAL-RECORDING-TAPE-1-2-x-5000-NEW-FACTORY-SEALED-/111929790369?hash=item1a0f890fa1:g:xwgAAOSwYlJW3y7~

[astrotoy]

Thanks, Dan.  I'll see whether there are any other clues about the provenance of these thin tapes.  They were safety masters.   Larry