Secrets of Shooting Film (Kodak Vision3 250D/500T) and ECN-2 Process Remjet Removal

1. Why does the film roll have an extra layer of "black carbon (Remjet)" than the ordinary civilian film?

Kodak's Vision3 series of motion picture films (such as 50D 5203, 250D 5207, 500T 5219) are the pinnacle of human color silver salt chemistry, with a dynamic range of up to 14 stops. However, the film is rapidly rubbing against the film in the camera at a speed of 24 frames per second, which will produce huge static sparks and halo reflections.

• Toner anti-halation and anti-static layer: Kodak applies a layer of black opaque carbon layer (Remjet Layer) composed of fine carbon black particles and acidic polymer binder on the outside of the film base on the back of the film.
• Fatal Taboo: Film rolls must never be thrown directly into the C-41 automatic developing machine (Noritsu/Jobo) in ordinary civilian developing shops! The carbon layer falls off in the developer, and the black ink-like toner will instantly contaminate the entire expensive medicine tank, and will adhere to all subsequent customers' films to form permanent black stains, causing the machine to be scrapped.

2. Carbon layer pre-washing, softening and alkaline formula and manual carbon removal techniques

The film roll must first go through a special pre-bath (Pre-bath PB-2) to soften and clean the carbon layer before official development:

• Official PB-2 Pre-wash Recipe (1000ml water):
• Borax (Sodium Tetraborate Decahydrate): 20.0 g
• Sodium Sulfate Anhydrous: 100.0 g
• Sodium Carbonate Anhydrous: 10.0 g
• Simple household baking soda and warm water method: If you do not have professional chemical reagents, you can add 20 grams of edible baking soda (sodium bicarbonate) to 1000ml of 40°C warm water.
• Carbon washing practice:

1. Pour the 40°C pre-wash alkali solution into the developing tank, continue to shake vigorously for 30 seconds to soften the polymer adhesive with the weakly alkaline liquid, and pour out the ink-black sewage;
2. Immediately pour 40°C warm water, shake vigorously with both hands for 15 seconds and pour out;
3. Repeat water flushing 4 to 6 times until the poured water changes from black ink to completely clear and transparent;
4. Then follow the normal ECN-2 or C-41 process for development and bleaching;
5. Ultimate washing and carbon removal inspection after fixing: After the fixing and washing is completed, open the lid of the tank and pull out the wet film, put on powder-free latex gloves, and gently pinch the back of the film (the emulsion-free black film base) with the pads of your index and middle fingers in a basin of flowing warm water like scissors, gently rub it from beginning to end with the flow, and thoroughly wipe away any carbon residue remaining on the back.

3. 500T’s “T (Tungsten)” color temperature calibration secret method

Kodak Vision3 500T is designed for color temperature balancing of 3200K indoor tungsten lamp.

• If you shoot directly under the scorching sun during the day, the film will appear extremely cold and exaggerated Avatar Dark Blue Cold Tone;
• Daytime shooting solution: Screw an 85B Amber Orange Temperature Conversion Filter on the front of the lens to accurately convert 5500K daylight to 3200K. Note that the 85B filter will attenuate the amount of light entering by 2/3 stops. At this time, the camera metering ISO should be set to EI 320 for exposure.

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