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HOW TO DETERMINE YOUR PERSONAL FILM SPEED
SIMPLIFIED VERSION

1. Cut the manufacturer's ASA in half and read an evenly lit board. Light should be balanced and surface smooth. Focus camera to infinity and the frame should include only the board. Be careful not to shadow the board.
   
   
2. Set the aperture FOUR STOPS LESS than the indicated exposure at half the ASA or Zone I. Place aperture at f-11 and meter for speed.
   
   Example: T-MAX 100 at 1/2 ASA or 50 ASA.
   
   To determine Zone I you decrease 4-stops less than indicated exposure --
   
   f-11 @ 1/15 = Zone V (indicated exposure)
   f-11 @ 1/30 = Zone IV
   f-11 @ 1/60 = Zone III
   f-11 @ 1/125 = Zone II
   f-11 @ 1/250 = Zone I
   
   
3. Shoot four frames at 1/3rd-stops in direction of less exposure.
   
   Use aperture stops not speed to bracket. Don't expose below 1/2 second.
   
   Bracketing 1/3rd-stops
   
   

   Frame	#1 f-11	@ 1/250	= ASA 50
   	#2 f-11 1/3	@ 1/250	= ASA 64
   	#3 f-11 2/3	@ 1/250	= ASA 80
   	#4 f-16	@ 1/250	= ASA 100

   
   
4. Shoot one black frame.
   
   Frame #5 Blank or no density -- cover lens.
   
   
5. Record all exposure settings and ASA on "Film Test Worksheet"
   
   
6. Shoot Zone VIII or 3-stops more than indicated exposures at 1/2 ASA.
   
   To determine Zone VIII or 3-stops more than indicated exposure, you start from indicated exposure or Zone V again.
   
   

   Frame	#6 f-11	@ 1/250	= ASA 50
   	#7 f-8 2/3	@ 1/250	= ASA 40
   	#9 f- 8 1/3	@ 1/250	= ASA 32
   	#10 f-8	@ 1/250	= ASA 25

   
   
7. Record exposure settings.
   
   
8. Expose remainder of film and process normally.