Hi, Steve,

Since Dave tossed it up to me, I'm afraid it got slowed down in the 
heavy traffic of the 404 <smile> and I'm only just seeing this.

You have the answers I would have provided, including the 10x measurement.

The "mil" sizing is indeed for the base film only in US tapes, but the 
50, 35, 25, and 18 micron sizing is the full thickness of the tape 
(nominally) in the non-USA scheme, eg Maxell UD35 vs UD50 (long play vs 
standard play, 1800 vs 1200 feet on a 7" reel). The IG Farben table that 
I helped Friedirch Engle by formatting and uploading is, I believe, the 
full tape thickness. The late Del Eilers's table gives the overall 
caliper as well.

It's all very confusing.



On 8/19/2016 11:01 AM, Steven Smolian wrote:
> What is the best method at reasonable cost of measuring tape thickness of a
> large number of  tapes?  I'm using a digital micrometer and getting results
> tat don't match the conventional .05, 1.0, 1.5 mil measurements.
> Am I squeezing the jaws too tightly?
> Steve Smolian
Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada                             647 479 2800
Quality tape transfers -- even from hard-to-play tapes.