Rem-Jet

AgX · Oct 19, 2008

I know about the structure, property and function of the rem-jet layer.

But what is the meaning/origin of that designation?

Up to now I could not find an explanation, neither on my bookshelves nor on the net.

Paul Goutiere · Oct 19, 2008

Maybe I'm wrong but from what I remember the term, Rem Jet, refers to the intense spray of water in the processing system that removes the layer. A Jet of water, that Removes the layer.

AgX · Oct 19, 2008

Paul,

After posting I got that idea that `rem´ could be related to `remove´, but still had no idea about that `jet´ part.
I guess I still would not designate that layer this way, but your explanation makes sense at least.

Photo Engineer · Oct 19, 2008

I heard once that "Jet" referred to the "Jet Black" carbon that was used in preparing the backing. IDK if it was true or not.

PE

AgX · Oct 19, 2008

removable Jet Black layer...

Makes sense too.

That `remove´ part would definitely make sense as other layers of that function are just decoloured in one way or another .

Funny though that this designation seems a bit mysterious.

Paul Goutiere · Oct 19, 2008

I have a few rolls of exposed Kodak 5247 (rem jet movie film) loaded in 35mm cannisters I shot, but never processed since 1980. (yes, 28 years old!!)

Anyone know where this stuff can get processed now? I think it is still C41 but that backing will come off and gum up regular processors.

JBrunner · Oct 19, 2008

Paul Goutiere said:
I have a few rolls of exposed Kodak 5247 (rem jet movie film) loaded in 35mm cannisters I shot, but never processed since 1980. (yes, 28 years old!!)

Anyone know where this stuff can get processed now? I think it is still C41 but that backing will come off and gum up regular processors.

It's not C-41, it's ECN-2. If you can get the Rem Jet off, you can process it C41, but it will look cross processed. Latent images on MP film that old will likely be gone towards blue and have developed some grain, so I'd stick to normal. The best lab I have experience with is Ford in Seattle. They were bought out by AphaCine, and now the techs are there. I had my last ECN project (Sept.) processed by them, and all was well.

Here is their website:

http://www.alphacine.com/

Photo Engineer · Oct 19, 2008

Paul Goutiere said:
I have a few rolls of exposed Kodak 5247 (rem jet movie film) loaded in 35mm cannisters I shot, but never processed since 1980. (yes, 28 years old!!)

Anyone know where this stuff can get processed now? I think it is still C41 but that backing will come off and gum up regular processors.

There was an ECN process in the 60s that I have the formulas for, but it was changed for the more recent flavors. IDK when the changeover took place.

PE

Paul Goutiere · Oct 19, 2008

JBrunner said:
The best lab I have experience with is Ford in Seattle. They were bought out by AphaCine, and now the techs are there. I had my last ECN project (Sept.) processed by them, and all was well.

Here is their website:

http://www.alphacine.com/

Thank you Jason,

I'll see if they will still do it....and if they do.....I'll have 'em do it.

Paul

patrickjames · Oct 19, 2008

Maybe a dumb question, but are there any c-41 movie films? Or films that can be run through c-41 (i.e. no rem_jet backing)? I have been curious about this for awhile.

Patrick

Michel Hardy-Vallée · Oct 19, 2008

When was remjet invented? Probably before Kodachrome?

The word always remind me of "ramjet", those special aircraft jet engines without motors. "ramjet" dates from 1942 according to the Merriam-Webster.

Photo Engineer · Oct 19, 2008

It was invented for Motion Picture. The high transport rates through the camera create a high level of static electricity. At least, that is my take on this.

PE

Ray Rogers · Oct 19, 2008

patrickjames said:
Maybe a dumb question, but I have been curious about this for awhile.

Patrick

Patrick, I have an old question too.
Do you still have that package of Gevaert paper you mentioned eons ago?

Ray

Frank Szabo · Oct 19, 2008

Photo Engineer said:
It was invented for Motion Picture. The high transport rates through the camera create a high level of static electricity. At least, that is my take on this.

PE

... and carbon being a metaloid (conductor of sorts) ...

Makes sense.

AgX · Oct 20, 2008

Patrick,

All print films made by Agfa and by Kodak do not have a rem-jet layer any longer.

(Both companies have got their own type of lasting anti-static coating.)

Tusker · Oct 20, 2008

WAY OUT

Well the only reference I know of would be to a SMITH & WESSON handgun cartridge invented in the early 1960's. It was a bottle-necked style and had problems backing out the brass when the gun was fired, locking things up. For that reason it had a very small following. If chambers were kept dry ' no oil' and the brass was dry, they worked fine. Long out of production, they are mostly collector items these days, except those of use who use them.
Here is mine, and yes, those are old Ivory stocks. The inserts you see in the photo are put in the chamber and use to fire .22 Long Rifle Cartridge's.
ca. 1961 , a first year gun.

AgX · Nov 5, 2017

Photo Engineer said:
I heard once that "Jet" referred to the "Jet Black" carbon that was used in preparing the backing. IDK if it was true or not.

Yes. Amongst the various grades of standardized carbon black pigments one grade is called Jet.

trendland · Nov 6, 2017

AgX said:
I know about the structure, property and function of the rem-jet layer.

But what is the meaning/origin of that designation?

Up to now I could not find an explanation, neither on my bookshelves nor on the net.

Ram-Jet have different task funktions :
(in order of importance)
1) reducing the frictionel resistance

*( high speed cameras are with 300frames a second - I personaly saw a prototye from a UK based company with
600 frames )

2) avoiding electostatic charge

(Notice : The more film lenght [300ft/1000ft] - the more speed = the more possible danger)
You will not see this phenomenon with
120 films ....

..!

3) in addition : anti halation protection from emulsions within/between color layer is the normal case to c41/E6 films.
Motion picture films got this protection
(out of practical concerns I just guess - so I am not sure 100%) into/within the
ram jet.
This together should also explain some
quality issues from CineStill films.

with regards

trendland · Nov 6, 2017

Oh sorry I made a little misstake from spelling : Ram Jet is wrong.
Perhaps because I know RamJet as term a little longer in comparisson to Rem-Jet.
Well - this is a RamJet Turbine !
And here it is in action :

with regards

lonelyboy · Nov 6, 2017

trendland said:
Ram-Jet have different task funktions :
(in order of importance)
1) reducing the frictionel resistance

*( high speed cameras are with 300frames a second - I personaly saw a prototye from a UK based company with
600 frames )

2) avoiding electostatic charge

(Notice : The more film lenght [300ft/1000ft] - the more speed = the more possible danger)
You will not see this phenomenon with
120 films ......!

3) in addition : anti halation protection from emulsions within/between color layer is the normal case to c41/E6 films.
Motion picture films got this protection
(out of practical concerns I just guess - so I am not sure 100%) into/within the
ram jet.
This together should also explain some
quality issues from CineStill films.

with regards

Yes, this is absolutely correct. Remjet has exactly these 3 functions.

carlostaiwan · Nov 6, 2017

I wrote an article on Rem-Jet, explaining What is the rem-jet layer and how to remove it. I hope you guys find it interesting
https://carlosgrphoto.com/2017/06/18/what-is-remjet/

georgegrosu · Nov 6, 2017

The dorsal carbon layer is the best antihalation layer (rem-jet) for the color negatives films.
For the positive color films, the antihalation layer was replaced ~ 1995-2000 with other light retention systems. (mare ecological)
As early as 2000, the color positives films had no graphite on the back (Agfa, Fuji and Kodak).
With my English, I think rem-jet comes from "remove" and "jet" refers to the water jet for cleaning the film.
The water jet is very important to be perfect (line) to clean the support.
You can read more about the dorsal graphite removal systems here:
https://www.kodak.com/Kodak/uploade...t_en_motion_support_processing_h242_h2402.pdf - page 2-6 .. 2-8.
High-speed filming uses also negatives that do not have dorsal grafit layer and is no problem.
The dorsal layer must have three properties: antihalation, antistatic and anti-twist.

George

Photo Engineer · Nov 6, 2017

As I believe is said above - REM = removable and JET = jet black carbon, a type also mentioned above. It is simply an abbreviation.

PE

AgX · Nov 6, 2017

trendland said:
Ram-Jet have different task funktions :
(in order of importance)
1) reducing the frictionel resistance
2) avoiding electostatic charge
3) in addition : anti halation protection from emulsions within/between color layer is the normal case to c41/E6 films

Using carbon black is a very old fashioned way. As such that would not be bad, but its most obvious drawback is that it neccesitates removal of that layer, even in a seperate action.

For all 3 issues the photo-chemical industry got meanwhile better solutions.

AgX · Nov 6, 2017

Photo Engineer said:
As I believe is said above - REM = removable and JET = jet black carbon, a type also mentioned above. It is simply an abbreviation.

Not that simple, as my primary question shows.

For instance I never ever heard the term "jet black" being used. And thus likely other non-native speakers have not either. So for them the term "Jet" remained enigmatic.

And I assume even most native speakers do not know the origin of the term "jet black".
It comes from "Jet", a mineraloid: black, fossile wood.

Rem-Jet

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