Thanks, Goran, I missed that when looking at the same site yesterday!
I do not have a complete understanding of print-through, but there is
something I think I know: While an ideal tape would be made with
magnetic particles that had the same ability to hold their field, in
reality, there is a statistical distribution (I'm specifically not
saying "Gaussian") of magnetic particles in tape. The problem particles
are the ones that are easily magnetized.
Some will always be flipping magnetization (sometimes referred to as
"thermal idiots") and that number increases with temperature. Also, as
noted elsewhere, external bias contributes to the print through
phenomenon. The 0.5 G magnetic field of the Earth contributes to it.
So yes, the thermal idiots and their close cousins will forget once they
are removed from the magnetic influence that caused them to all march in
line in the first place.
There was a brief mention of tape lifters reducing print-through when
the tape is wound over them. If they are magnetized, that would be
equivalent to skimming. Skimming is mentioned in the Echoraser AES paper
[Radocy, Frank. 1959. "A New Device for the Reduction of Print-Through"
Vol 7, No 3. July. p129-132. E-lib ID 6258]. However, there is the
possibility that magnetostriction may also be a factor. Sharp bending
radii (sharp as in relation to recorded wavelength) may cause partial
erasure in some recorded media. Unfortunately, this effect was never
fully explored to the best of my knowledge.
The Bertram paper I mentioned yesterday is Bertram, H. Neal, Michael K.
Stafford, and David R. Mills. 1980. "The Print-Through Phenomenon" Vol
28, No 10. October. p690-705. E-Lib ID 7738. In glancing through it is
well worth obtaining, but will require in-depth study.
On 2015-03-13 9:28 AM, [log in to unmask] wrote:
>> That is the part I don't understand.
>> Why would it propagate outwards
>> more easily than inwards? It's the
>> same distance either way.
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada 647 479 2800
Quality tape transfers -- even from hard-to-play tapes.