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18 KODAK VISION2 Color Negative Control Strips, Technical Data and Crossover Information
Control-Strip Crossover
Important: During the inventory crossover from the old
VISION Control Strips to the new VISION2 Control Strips,
every effort should be taken in your operations to avoid
switching back and forth. Your process control will be
greatly simplified by depleting your supply of the VISION
Control Strips (except for what is needed for crossover
purposes) prior to utilizing the VISION2 Control Strips.
There will come a time when you will need to begin using
a new batch of control strips. A new batch means a new code
number, not a fresh box of strips with the same code number.
Please be aware no two batches of control strips are
identical because of slight differences in product, exposures,
process, etc. And therefore, the aim value numbers will not
match (however, on rare occasions they could), even with
the application of the deviation factors.
When you first started using control strips, you had no
previous reference and you set up your aim value parameters
by reading the densities of the specified (D-min, LD, MD,
HD, or D-max) control reference steps and applying the
deviation numbers supplied with that batch. Using a new
batch of strips is really no different, except you will have a
new set of aim numbers,
As the time approaches to change to a new batch (code),
you will want to make a “crossover” from the current, or old
batch. Crossover simply means to adapt to a change in aim
numbers, not a change in processing technique. You should
begin the crossover with at least a week’s supply of strips
still available (never wait until you run out).
The crossover to a new batch lets you get a “feel” for the
new set of aim numbers. Do not attempt to match the new
aim numbers to the old ones. If you do, you probably will
find it necessary to change the mechanical and/or chemical
specifications of the process, and this will most likely lead to
a non-conforming unacceptable process. You will notice
some differences in the way the new batch trends as
compared to the previous batch. this is a normal batch-to-
batch variation, and is to be expected. If you are unable to
maintain a plot within your action limits with the new
control-strip batch, call your Kodak representative to assist
you.
Use the following crossover procedure each time a new
code number is put into service:
• Determine the aim values for the new batch, the same as
you did for the current or old batch by reading the
specified steps (D-min, LD, MD, and HD or D-max) of the
reference strip and applying the correction factors. If there
is more than one roll of the same batch, average the
corresponding step densities for all reference strips in the
batch, then apply the correction factors.
• Process an old and new control strip simultaneously at
least three separate times. Do this at different times of the
day, and better yet, on different days, until you have a
number of pairs. During this time, continue to control the
process with data from the old strips.
• Post the new aim values on the same form as the old,
leaving an appropriate space between the two aim sets (as
illustrated in Figure 14). This way you can see the
differences of each control strip reaction at a glance. You
will observe the tracking of the “old” batch as compared
to the “new” batch, with each plotted to its individual set
of aim numbers. Both should be tracking in similar
directions, but not exactly. However, they still should be
within the same action and control limits. Please
remember, no matter how the aim densities differ in
numerical value, you still use each set as your zero (0)
reference line.
• Once you are comfortable with the new batch of control
strips, use a new H-24F or Y-55 form to separate and not
confuse the old and new aim numbers while making the
daily notations.
• If, for some reason, there is a need to adjust the process to
conform to the new batch of control strips to new action
and control limits, cease processing and evaluate the
entire system. Such a need for change indicates a
fundamental system difficulty, which most likely involves
all aspects of the process, not necessarily a problem with
the new batch of control strips. If difficulty continues,
contact your Kodak technical representative.