Film Chemistry Diagnostics
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Diagnostic procedures on chemical trouble.

This chemical diagnostic is assuming your colour balance and light bulb conditions are correct. Do not proceed with these diagnostics unless you are sure. Chemistry troubles are consistent. That means, your productions are consistently having same trouble regardless how you correct them through other means. If you could still get some good pictures. Your trouble is probably not caused by chemistry. Film damaged by heat, or through long storage after exposure can be mistreated as chemistry trouble. To differentiate the trouble caused by film chemistry or paper chemistry, test print a known good negative. If test print O.K., check your C41 film chemistry. If test print is bad, check the paper developer first. If you still have trouble after correcting the paper chemistry, Check the film chemistry.

C41 film developer diagnostics

PH value for film developer: 10.00.05

Part A: For PH control. It gives you the correct colour.

Part B: Antioxidant. It prevents your developer from oxidation.

Part C: Developing agent. It performs the colour developing function.

Symptom

Cause

Correction

Prints lack contrast. Under developed. Add density booster. Check PH. Adjust replenishment rate.
Over developed. High contrast. Colours correct. Over replenished. Add density reducer. Check PH. Adjust replenishment rate.
Over developed, cyan colour on all prints. Replenishment is normal. Developer carried over to bleach and fixer. Add bleach/fix PH reducer to bleach and fixer.
Cyan colour on all prints, colour can not be corrected. Developer contaminated with bleach. Discard and restart with new developer.
Cyan colour on all prints, colour can be corrected. PH too high. Use PH reducer.
Red colour on all print. Can be corrected. PH too low. Use PH booster.
Colour still off even PH is correct PH meter not correct. Calibrate your PH meter.
Negative foggy. Dmin high. Over developed Add antifog or density reducer.
Developer is new. Prints appear cyan, foggy, and over developed. No starter. Use starter, dilute if necessary.
Filter plugged in short time. Low utilization Use antioxidant.
Red control curve high. PH too high. Add PH reducer.
Red control curve low. PH too low. Add PH booster.
Blue control curve high. Over developed. Add density reducer.
Blue control curve low. Under developed. Add density booster.
Blue Dmin high Not enough turn over. Increase replenishment rate.

C41 Bleach diagnostics:

PH: 6.50.5.

Silver image (black & white) at film base. Bleach too weak. Use bleach booster.
Red curve low Leuco-cyan-dye Use PH booster.
Crystallization. Water vaporization. Add water.

C41 Fixer diagnostics:

PH: 6.50.5.

Negative not transparent and foggy. Blue cast on print. Fixer too weak. Add fixer concentrate into working tank. Increase replenishment rate.
Sulphur deposits. Oxidation or too much bleach carry over. Use fixer antioxidant.
Crystallization. Water vaporization. Add water.
 

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