Deep Tank Processor Chemistry Conversion Procedure

This procedure is a guide to a smooth transition from one manufacturer's chemistry to another, or from one chemistry type to another, in deep tank processors.

Highlights

• Before shutdown, the control strip reference step must be within the allowed range and its value recorded
• Fresh developer gives higher density; season the new chemistry or mix one gallon of the old developer with the new chemistry
• Finally, adjust transport speed until within ±.02 of the recorded reference density

Before shutting down the processor

• Run the process control routine twice to confirm stability
• Without a sensitometer, monitor the LD and RD steps of the pre-exposed strip
• Check production work to rule out a control strip error

Conversion steps

1. Turn off the heating elements
2. Drain the processor and replenishment system
3. Remove the filters and reinstall the housings without new filters
4. Wash and clean the tanks and rollers; for heavy silver deposits, use Imagelink Developer Systems Cleaner
5. Fill the processor and replenishment system with clean hot water
6. Circulate the water for 30 minutes with the transport drive on at zero speed
7. Drain the replenishment system and fill it with the new chemistry at the specified ratio: Microfilm Developer 1:7 (specific gravity 1.045 to 1.055) and Microfilm Fixer 1:3 (specific gravity 1.085 to 1.105)
8. Set the replenisher according to film width, film type and transport speed per the manufacturer's manual or Pamphlet D-30
9. Drain the processor
10. Install new filters on the recirculation pumps
11. Fill the tanks with the new chemistry, preferably through the replenishment system
12. Turn on the heating elements and bring to the specified temperature
13. Once the temperature is stable, set transport speed for the correct dwell time
14. Splice and process 5 customer control strips in the darkroom
15. Record the average reference step density
16. Adjust transport speed until within ±.02 of the reference density recorded before the chemistry change

For more information, refer to D-17 Control Procedures for Source Document Microfilm Processing.