Rite Life 394 用户手册

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页码 28
Variations in processor conditions are monitored 
on this step. 
• 
Contrast Index: An indicator of the slope of the 
straight-line portion of the D-Log E Curve is 
called Contrast Index. Select the step closest to 
but not larger than 2.20D. Subtract from this step 
the step closest to but not lower then 0.45D. 
Contrast Index is used to monitor processor 
variations in conjunction with the Speed Index. 
FIGURE 1.  D-Log E Curve 
Optical density versus relative log exposure for typical 
radiographic film. 
 
 
Selection and Use of Film 
CONTRAST INDEX 
SPEED INDEX 
BASE+FOG