Mark Sampson , Jun 16, 2003; 11:21 a.m.
1) Very long 'straight line' in its characteristic curve. That meant long density range negs can be made that hold highlight seperation, very useful for alt-process people who need contrasty negatives. 2) Characteristic curves the same for red, green, and blue. This was critical for those making color-separation negatives, especially dye-transfer printers. (S-XX was discontinued at about the same time Kodak dropped the dye-transfer process, circa 1991). 3) Very grainy, as befitting a 'high-speed' film invented in the 1940's.