KING FILM 5203 - 50D 135/36

What is an ECN?

ECN, Eastman Color Negative, is a photographic system for processing color cinematographic negative film created by Kodak and used from the 1950s to the mid-1970s. Advances in research and development brought improvements to the original ECN, including a faster yet more environmentally friendly negative processing process.

The original ECN was thus replaced by an improved processing system designated ECN-2. This became the industry processing standard for all contemporary negative colour cinematographic film and remains so to this day.

In short, ECN-2 is a development process designed to address the specific processing and characteristics requirements of motion picture films. Of course in principle it shares many things with the film processing we use for conventional still photography, but it has features that allow faster processing of motion picture negatives in the order of meters per minute along with the removal of the REM-JET layer.

The question then becomes. Isn't the ECN-2, after all, just a sort of C41 in disguise?

From a chemical point of view, the answer is clear: No. ECN-2 and C41 have different chemical compositions and therefore different properties. From a practical point of view, however, the answer is more complicated. If we decide to develop a motion picture negative with, for example, the Kodak Vision C41 process, the difference to using ECN-2 will be the necessity to manually remove the REM-JET layer and, of course, the final result. If we ignore the REM-JET layer removal, contamination and degradation of the C41 will occur which will definitely not be a pleasant surprise.

What is REM-JET

We have already talked a little about ECN-2, where we have repeatedly mentioned the mysterious abbreviation "REM-JET" behind which hides a black opaque, anti-halation, protective carbon layer with anti-static properties deposited on the underside of the film base.

REM-JET Antihalaxing properties

Prevents halation - the phenomenon whereby light rays that have passed through the emulsion are reflected off the substrate (film base) and re-penetrate the emulsion from behind, causing unwanted glare. This is explained by the black colour of the REM-JET layer.

REM-JET Antistatic properties

When the film moves rapidly during exposure, many camera elements cause friction which generates static electricity. This, believe it or not, can be released from the camera structure directly into the film emulsion and cause irreversible damage. When this happens, the electricity burns its image into the frame in the form of a branching flash like we see in the sky during heavy thunderstorms, but which would be visible on the silver screen or screen every "x" shots rendering the exposed negative unusable.

REM-JET Mechanical protection

When shooting cinema, the film in the camera moves at 24 fps (frames per second) which is about 45 cm/second and that's not exactly a slow pace. So REM-JET also protects the base layer of the negative from mechanical damage during in-camera exposure such as scratches etc.

REM-JET must be removed during processing of the negative. This makes the processing process a little more complicated than with conventional film for still photography, but it is not a fundamental or insurmountable problem. In our conditions we can use a solution composed of lukewarm water and ordinary baking soda to remove the layer.

So when it comes to naming it REM-JET, it is actually an abbreviation for the process of removing this layer REMove by water JET" "remove by water jet" How simple.