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

anon-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.

18	KODAK VISION2 Color Negative Control Strips, Technical Data and Crossover Information