Date Type Hc Retentivity Remanence Thickness WTD
S/N Base Film
(Oe) (G)
(nWb/m) (mils) (dB)
1948 Scotch 112 170 450 715 .70 Acetate
1948 Scotch
111 270 920 1015 .44 0 dB Acetate
1962 Scotch 202 315 790 1015 .51 5 dB Polyester
1969 Scotch 206 320 1050 1430 .54 5+3 Back coated polyester
1974 Scotch 250 380 1200 1985 .65 Back
coated polyester
1979 Scotch 226 370 1400 1985 .56 5+5.8 Back coated polyester
1971 Ampex 406 290 1150
.50 Back coated polyester
1974 Ampex 456 295 1400
.50 Back coated polyester
1990 Scotch 996 360 1700 2700 .63 5+8.5 Back coated polyester
Quantegy GP9 350 1500
.69 Back coated polyester