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7
5. After processing of film is complete, record the
date, time, and processor identification number on
the film in the designated areas.
Manual Data Recording
Procedure
Establishing Normal Speed Index, Contrast
Index, and Base+Fog
The normal speed index, contrast index, and base+fog
values are established on a representative film, when
the processor is considered to be operating in an
optimum fashion.
Run several film samples and determine the average
values for speed index, contrast index, and base+fog,
using a transmission densitometer. Step wedge areas are
as uniform as is possible to produce. There are,
however, some errors at the edges of the step area.
Therefore, always measure density at the center of
the step. Use a 2mm aperture to give best repeatability.
Record the following data on the process control
record.
• Developer Temperature - Temperature of
developer solution in processor during processing
• Normal Base+Fog - Step number one density, the
least exposed step on the wedge.
• Normal Speed Index - The density of the step
closest to 1.0D + base+fog. The step number
should remain the same for a given processor and
film type.
• Normal Contrast Index - Select the step closest
to but not larger than 2.20D. Subtract from this
step the step closest to but not lower than 0.45D.