How can rem-jet be removed from motion-picture film for still-photo processing?
Asked 12/15/2015
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2 answers
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Motion-picture color negative film has a rem-jet anti-halation backing on the base side. If you bulk-load or shoot it as still film and process it outside a commercial ECN-2 machine, what practical methods are used to remove rem-jet without damaging the emulsion? Is it better to remove it before development or after processing?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
10y ago
2 Answers
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The Rem-Jet coat is a dispersion of lamp black (soot) in a binder of cellulous acetate phthalate. This binder is an “acid plastic”. It can be softened and washed away using an alkaline solution. Machine processing uses a pre-bath to temporarilly harden the film so it better withstands transport in a fast moving film processor. The pre-bath softens the Rem-Jet and spinning rollers, much like paint rollers scrub off the Rem-Jet.
You can make an alkaline solution and hand buff with a well washed “T” shirt. This can be performed the film has been processed but before drying. Water 27 to 38°C (80 to 100°F) 800 mL 800 mL Borax solution 15 g/L use 20g Sodium Sulfate (Anhydrous) 100 g Sodium Hydroxide 1.0 g Water to make 1 L
The Rem-Jet serves to protect the film from exposure from the rear. Many motion picture cameras with thru-the-lens viewfinders leaked light if the photographer looked away. It serves as an anti-halation backing. It protects the film when large rolls are loaded and unloaded in subdued light.
Originally by user44949. Source · Licensed CC BY-SA 4.0
user44949
10y ago
0
Generated from our catalog & community — verify before relying on it.
Rem-jet is designed to be removed by an alkaline prebath in the ECN-2 process, then washed/scrubbed off before development. In home processing, fully duplicating the machine process is difficult because proper removal normally relies on chemistry plus mechanical action, and incomplete removal can leave black particles behind.
From the answers, the safest practical home approach is often to process the film first, then remove remaining rem-jet under running water with very gentle wiping on the base side only, followed by a final rinse/wetting agent. This avoids trying to scrub the film before the image is stabilized, though it can dirty your chemistry.
If you do use a prebath, it should be alkaline; one answer gives a borax/sodium sulfate/sodium hydroxide formula to soften the rem-jet so it can be gently buffed away. Extreme care is needed: aggressive manual scrubbing can damage the emulsion or redeposit rem-jet particles onto the film.
So, best practice from the provided advice: use proper ECN-2 chemistry if possible; otherwise expect a compromise, use an alkaline softening step or remove rem-jet after development, and handle only very gently.
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