I first wrote about seeing the tracks here in March of 2006. While these solutions work, the Plastiform viewer needs to be kept in a humidor and the Kyread spray is a bit of mess to use and the results are variable. One result of the Kyread treatment can be seen here (please wait for the pictures to load, it’s a big page).
Here is what appears to be a vastly improved solution:
This has been updated 2015-07 and now 2005-11. We ordered a new 1022 viewer from Arnold/Flexmag as the 2007 Sigma finally gave up the ghost and the 2011 Sigma that I had as a spare is not as good a performer for this application. As of the end of November, we are still awaiting a response from Sigma. Overall, I am quite pleased how well the “fresh” Arnold unit works and it appears more sensitive than the older 3M unit I had even when it was working well. This is now my top choice. It is not perfect, but fits the budget better and performs much better than the newer Sigma. It is also faster than the Sigma ever was.
Please look here, but there is still good information, below.
Two ways of seeing tracks on a tape are listed here. We’re collecting more in the comments.
We are currently working on some un-published tapes for a major Canadian folk artist. We have a 7.5 in/s 2-track stereo recording that was one of (if not the) first studio recording of this artist from circa 1972.
At some point, this tape was played on a 1/4-track machine that injected hum onto the left channel. Here’s what the magnetic viewer showed:
I remain a fan of the Sigma MV-95 magnetic viewer despite its slowness at times. I discussed it at length here in June of 2007. It has helped analyze many problematic tapes and has helped me understand the issues enough to apply the correct solution to transfer damaged tapes.
An example is here.
In several articles on magnetic viewers, we have discussed the spray-on Kyread product.
GOOD NEWS! The company is back! I received a phone call from Ryan Blackwell this afternoon and he pointed me to their new website. The company name is now Kyros Technologies LLC.
Note their jump into the 21st century with a real website and great domain name: magneticdeveloper.com — they even have a shopping cart for online ordering. This is apparently the same product I’ve been using for the last eight years.
This page provides a table of signal wavelengths for different speeds and frequencies. It is sometimes useful in understanding bandwidth limitations at the high end for a particular head. The first null occurs when the wavelength of the signal is about 112% of the optically measured length of the gap. A common place to set the gap length is for a 4 dB loss at the highest frequency of interest. This corresponds to the half wavelength indicated in the table below. See Mallinson, John C., The Foundations of Magnetic Recording, Academic Press, San Diego, 1993. pp 95–96.