How to remove Remjet

ECN-2 film, commonly used in motion picture production, has a special black carbon-based layer called rem-jet on the back of the film. This rem-jet layer helps to reduce halation (light scattering) during filming but needs to be removed during the development process. If you’re planning to develop ECN-2 film at home using C-41 chemicals, removing the rem-jet layer is an essential step. Here’s how to do it, including the official recipes for the prebath based on Kodak’s H-2407 publication.

Step 1: Prepare the Prebath Solution

The prebath is a crucial step that softens and loosens the rem-jet layer, making it easier to remove. Kodak provides an official recipe for the prebath solution in their H-2407 processing manual.

Kodak Prebath Recipe 1 (the original one):

Water	800ml (38°C)
Borax (decahydrate)	20g
Sodium Sulfate (anhydrous)	100g
Sodium Hydroxide (Lye)	1g
Water	to 1L

Mix the borax, sodium sulfate, and sodium hydroxide into the water until fully dissolved, then add more water to make up a total volume of 1 liter. The solution should be used at a temperature of 38°C (100°F) or 41°C depending on the color development process.

This formula contains chemicals that are corrosive and may pose long-term health concerns. Borax can also be hard to get in some regions (EU). Because of that, Kodak published alternative prebath formulas that omit the use of borax and sodium hydroxide.

Dissolve the carbonate and bicarbonate in the water completely, then top up with water to make 1 liter.

If all this sounds too complicated, check out this simplified Remjet recipe. We also offer pre-mixed rem-jet prebath based on the original formula in our Shop.

Step 2: Soak the Film in the Prebath

The following steps can take place at 38°C or 41°C respectively. Use the appropriate temperature based on the developer you use (C-41 at 38°C or ECN-2 at 41°C).

Use the Prebath: Prepare your film as usual by spooling it onto a reel and loading it into your developing tank. Then pour the preheated (process temp.) prebath solution you prepared earlier. Let the film soak for approximately 30 seconds. During this time, gently agitate the tank to help the solution evenly coat the film and further soften the rem-jet. After this, pour out the prebath. You can reuse the prebath up to 10 times using the stock solution or indefinitely by replenishing it (100 ml of fresh prebath every 5 rolls).

Step 3: Remove the Rem-jet Layer

After the prebath soak, the rem-jet layer should be sufficiently softened for removal:
Fill the tank with warm water (process temp.) half way and shake it vigorously for 10 seconds. Then pour the water out. The first washing will come out very dark. And the solution will clear up with every time. Repeat this step until the water runs out clear. (usually 3-5 times)

step 4: continue with developement

Once the rem-jet layer is removed, you can proceed with the development process as usual. If you’re using C-41 chemicals, simply follow the standard C-41 or ECN-2 processing steps from this point on.
Most of them will follow the same rough course:

Step 5: Additional Cleaning

Manual Removal: Especially with older film, the rem-jet layer might not wash away completely during the first removal process. Therefore, take out the roll after the last washing cycle, and using your fingers, a soft sponge, or a microfiber cloth, gently wipe the film’s base side (the non-emulsion side) under running water, or in a big tank filled with water to remove any residual rem-jet. Be careful not to scratch the emulsion.

Step 6: Final Rinse and Dry

• Stabilizing: Submerge your film into the final rinse/stabilizer bath, according to your chemical’s manual.
• Drying: Hang the film to dry in a dust-free environment.

Alternative Methods for Removing Rem-jet

Baking Soda and Water

A bath of warm water with a few tablespoons of baking soda can help soften the rem-jet, though it may require more manual scrubbing afterward.

Removing the rem-jet layer at home can be a bit intimidating at first, but with the right approach, it’s entirely doable. By following one of the official Kodak prebath recipes and taking care during the manual removal process, you can ensure your ECN-2 film is clean and ready for development. This step is crucial for achieving the best possible results when processing ECN-2 film using C-41 chemicals at home.