Reel to reel tapes info

When reel-to-reel tape was still a studio/consumer product, BASF followed a naming convention that defined the product type. In 1984 it became clear that open reel tape was only going to be a professional product in the future, and the naming convention changed with the introduction of "SM 910"--Studio Master 910. The US market named the consumer products differently, and that accounts for addition confusion. The general run down of products and naming conventions follows.

The product type was first defined by a two-letter designation describing the playing length, followed by a number defining the total thickness of the tape in microns. If the tape were back-coated, an "R" for "rueckseite" followed the playing length. The final letters, if they appeared, described the type of coating.

SP 50 = standard play for 50-micron tape with 1.5 mil base film; 1200' reels
LP 35 = long play for 35-micron tape with 1.0 mil base film; 3600'/1800' reels
DP 26 = double play for 26-micron tape with 0.75 mil base film; 2400' 7" reels
TP 18 = triple play for 18-micron C-60 cassette tape; 15,000' pancakes
QP 12 = quadruple play for 12-micron C-90 cassette tape; 23,700' pancakes
XP 9 = extreme play for 9-micron C-120 cassette tape; 10,800' pancakes

"LH" stood for "low noise, high output" oxide used for better than average performance. "LHL" was a formulation for low printthrough, and "LHS" was an advanced oxide with slightly higher coercivity intended for consumer use at slower 3.75/7.5 ips recordings rather than the more common 15 ips speeds used in the studios. So the SPR50 LHL from the late 1970s was a 1.5 mil backcoated studio tape with lower printthrough than normal.

For the US, the names differed a bit:

Performance = 3600'/1800' reels of LP35 standard oxide
Studio = 3600'/1800' reels of LP35 LHS for slower consumer speeds
Professional = 3600'/1800' of backcoated LPR35 LH for professional use

In the mid 1980s, it was "clear" to the marketing departments that open-reel was dead as a consumer product. In the US, the product managers tossed out scores of unopened boxes of open reel tape into a dumpster. I climbed in and rescued them all for preservation and my own use. The professional group continued to sell the product, of course, and the naming conventions changed to distinguish the use of the product.

LM 920 Loop Master chrome tape in 1- and half-inch width for loop bins
LM 921 Loop Master bin tape with an improved formulation
SM 910 Studio Master tape in widths from quarter inch to 2 inch; 50 microns
SM 911 Studio Master tape with reduced modulation noise that replaced 910
SM 468 Studio Master tape inherited from Agfa; very high coercivity
SM 900 Studio Master tape to compete with Ampex 499 and 3M 996
LPR 35 a throw back to the old naming convention for 1 mil tape

It should be noted that BASF, unlike Agfa, Ampex, and 3M, never used the polyurethane infamous for breaking down over time and causing sticky tapes. I've used a lot of open reel tape over the years, and there is no other tape that outperforms BASF mechanically. Maxell made a great open reel tape; but in published, independent comparison tests for electro-acoustic properties of consumer open reel tapes, BASF was the regular winner. All of the tapes I salvaged years ago still wind perfectly with no significant rub off and no sign of shedding.