Stand corrected on thickness of Efke 100, was confusing it with J&C's Classic film ( a 2 layer film). John Williams book Image Clarity has an excellent chapter on film types including a discussion of emulsion thickness. He includes Plus-X, Tri-X & HP-4 as thick emulsion films, and says such films dominate the market. Quoting him, "the thick emulsion & coarse grain of general-purpose films trade off sharpness for exposure latitude... their strength is not in their image quality."