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Why no rem-jet on 35mm stills?


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#1 grantsmith

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Posted 15 August 2006 - 03:56 PM

Hello,

Why is there no anti-halation backing on 35mm stills film?

Is it anything to do with motion?

Thanks,

Grant
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#2 Michael Collier

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Posted 15 August 2006 - 04:03 PM

I have always sort of wondered that myself. I assume the answer is because it would not be economical to upgrade every wallmart printer to remove the coating, and the added cost of chemicals to remove the coating would make the printing impracticle, given the modest quality return you would get. (My mom is one of the few amatures still shooting film in the US, but I have never heard her say 'oh my, There is way too much halation on this picture. ) I don't think many amatures would want to pay for the coating and removal. they might view it as a fantom feature with no real benifit.

....John?
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#3 Jesse Andrewartha

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Posted 15 August 2006 - 04:47 PM

There IS antihalation backing in practically all modern 35mm still films, but it's not rem-jet. Motion picture films and still stocks have different processing and formulations but have the same features... I think one of the only film without an anti-halation backing now is b+w infrared.

-Jesse-
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#4 grantsmith

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Posted 15 August 2006 - 05:01 PM

thanks jess. i can stop scratching my head now

*more head scratching sorry*

why dosnt motion picture film use the non rem-jet anti-halation backing? Wouldn't this make the cost of stock cheaper? John?
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#5 Robert Hughes

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Posted 15 August 2006 - 05:04 PM

Not being a film pro I can only hazard a guess, but it may have to do with the extreme level of blow-up involved from a 35mm print to the screen; anti-halation techniques that work for 5" x 7" paper prints may not hold up to the higher demands of movie film projection?
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#6 David Mullen ASC

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Posted 15 August 2006 - 09:36 PM

I believe the reason is the speed at which movie film runs through a camera, so the rem-jet acts as a lubricant and an anti-static protector -- this isn't much of an issue with still camera film, which is why it can get away with a simpler anti-halation backing.

The question for me is more, why doesn't b&w movie film use rem-jet? You'll notice that you do get some halation problems with b&w movie film, even though it has a simple anti-halation layer -- although some people like the effect around candles and headlights.
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#7 Charles MacDonald

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Posted 15 August 2006 - 10:06 PM

There IS antihalation backing in practically all modern 35mm still films, but it's not rem-jet. Motion picture films and still stocks have different processing and formulations but have the same features... I think one of the only film without an anti-halation backing now is b+w infrared.

-Jesse-

I belive that the design criteria included being able ot process in small tanks, where any coating that comes off would be a real pain. MP film Is ONLY proeced in long lenths in continuous processors so they can spec the rem-jet.

I belive most still film has a silver layer under the emusion that is bleached at the same time the other silver is removed. Compare some Still film with a scrap of raw MP negative with the Backing taken off, the still film is far darker from the back.
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#8 Nick Mulder

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Posted 15 August 2006 - 10:10 PM

B+W stills films do anti-halation layers,

otherwise you would see halation eveywhere...

You have to go to China, Russia etc to get films without it - the brand 'Lucky' for instance does not have a layer and is sought after by people looking for the effect
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#9 Chris Keth

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Posted 16 August 2006 - 01:04 AM

Not being a film pro I can only hazard a guess, but it may have to do with the extreme level of blow-up involved from a 35mm print to the screen; anti-halation techniques that work for 5" x 7" paper prints may not hold up to the higher demands of movie film projection?



That and still camera pressure plates can be blacked to cut down on reflections that cause halation. They don't have to deal with the large amount of film running through the camera smoothly. Motion picture camera pressure plates prettymuch have to be super-polished to cut down onf riction and scratches that wouldresult otherwise. Unfortunately, this surface is also super reflective so a better anti-halation layer is needed.

That's my theory. B)
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#10 John Pytlak RIP

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Posted 16 August 2006 - 07:44 AM

Rem-jet offers many advantages for a motion picture color negative film:

1. It is very effective in reducing halation, without the need to add additional dye or silver to the film

2. It is very conductive, and so greatly reduces static problems

3. Its frictional properties can be easily adjusted for optimum camera transport

4. Its surface is optimized to reduce the risk of ferrotyping in long rolls

5. It is removed during processing, so any superficial back-side scratches are removed with it

Historically, the ECN and ECN-2 processes have always included rem-jet removal steps (prebath, water spray-off, buffers), since the process was intended for professional motion picture labs, not home enthusiasts or the local drug store to run.

The black-and-white motion picture films trace their processing origins back to well before rem-jet was invented by Kodak. So they evolved and were designed for processes that did not include rem-jet removal.

Notably, KODACHROME film has used rem-jet since Kodak invented it over 70 years ago.
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#11 Sam Wells

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Posted 16 August 2006 - 09:46 AM

Notably, KODACHROME film has used rem-jet since Kodak invented it over 70 years ago.


Does this mean that Kodachrome still film has always had it too ?

-Sam Wells
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#12 John Pytlak RIP

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Posted 16 August 2006 - 11:46 AM

Does this mean that Kodachrome still film has always had it too ?

-Sam Wells


Yes. The "slate was clean" when KODACHROME film was introduced in the 1930's, and rem-jet provided the best antihalation and antistatic backing at that time. Since Kodak originally did all the processing, an additional rem-jet removal step was not a big issue in an already complex process sequence.
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#13 K Borowski

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Posted 16 August 2006 - 12:07 PM

Kodachrome has many firsts. It was the first color film to accurately depict colors, when it was introduced (stealing the name from one of it's lenticular prism predecessors) in 1936, the work of two classically trained Jewish violinists who dabbled in the invention of a color film in their spare time :-) Color negative was ineffective at the time because they had not yet perfected the orange color masking to minimize color contamination. Koadachrome probably contributed to the emergence of 16mm newsgathering, and 35mm still photography. I'd assume due to its great expense when it came out, these were the largest sizes it was available in: 16mm for movies, 35 for stills. I seem to recall that the same Kodachrome emulsion was used in both still and cine cameras too. Were it not for Kodak's discontinuation of K25 and K40A, there would have been two stocks available for both still and cine. Unfortunately volumes are down so low now that K64 and K200 are probably going to get the axe next. I think it is a shame because K-14 offers a truly unique color pallette compared to the E-series Ektachromes or Fuji's Velvia and Provia films.

~Karl

Edited by Karl Borowski, 16 August 2006 - 12:09 PM.

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#14 Leo Anthony Vale

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Posted 16 August 2006 - 01:02 PM

Kodachrome has many firsts. It was the first color film to accurately depict colors, when it was introduced (stealing the name from one of it's lenticular prism predecessors) in 1936, the work of two classically trained Jewish violinists who dabbled in the invention of a color film in their spare time :-)

Color negative was ineffective at the time because they had not yet perfected the orange color masking to minimize color contamination. Koadachrome probably contributed to the emergence of 16mm newsgathering, and 35mm still photography. I'd assume due to its great expense when it came out, these were the largest sizes it was available in: 16mm for movies, 35 for stills.
~Karl


---Only one of the Two Leos was a violinist, Godowsky. Mannes was a pianist.
Once I did quite a spit take while listening to Karl Haas on the radio rattling off the names of the great concert pianists of the 20th century, when he mentioned Leopold Godowsky.
Of coure that was senior. Junior being the Kodachrome violinist.
But Junior was the violin accompanist at his father's concerts.
One wonders why P.Simon didn't have a violin soloist in his song. Okay, with piano accompaniment.

Originally Kodachrome was going to be a two color process, someone at Kodak realized that it would be no great problem to add a third color layer.
Also Kodak had announced an introduction date. In case Man and God did not make the dead line, Kodak purchased additive Dufaychrome to be packaged as Kodachrome.

Kodachrome was availiable as sheet film until until, I think, the late 40s. I presume it was replaced by Ekta-
chrome.
Supposedly Kodachrome had streaking problems which most noticable on 35mm cine.
Yet Technicolr used 35mm Kodachrome as Technicolor Monopack.
& warners patented a 35mm optical additive printer for making color prints onto Kodachrome from a set of YCM masters. This was for a collor system that was squelched due to threats from Dr.Kalmus.

Edited by Leo A Vale, 16 August 2006 - 01:03 PM.

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#15 Charles MacDonald

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Posted 16 August 2006 - 10:29 PM

B+W stills films do anti-halation layers,

B&W Negative for both still and movie use actually is made on a GREY base for that purpose. Some of the OLD ADOX films actually had a dye layer on the back of the film which bleached itself out when it hit the chemicals. I rember the first time I tried a roll in Rodinal, and poored out developer that was almost black-purple from the dyes.
I suspect that some films may use the same special dye technique in the lowest layer of the emulsion. clearing by the time it emerges from the fixer.

The silver layer would only work for color negative or reversal films, where in both cases the silver layer would be removed.
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#16 John Pytlak RIP

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Posted 17 August 2006 - 02:13 PM

B&W Negative for both still and movie use actually is made on a GREY base for that purpose. Some of the OLD ADOX films actually had a dye layer on the back of the film which bleached itself out when it hit the chemicals. I rember the first time I tried a roll in Rodinal, and poored out developer that was almost black-purple from the dyes.
I suspect that some films may use the same special dye technique in the lowest layer of the emulsion. clearing by the time it emerges from the fixer.

The silver layer would only work for color negative or reversal films, where in both cases the silver layer would be removed.


Yes, other anti-halation methods are dyed base, anti-halation dyes under the emulsion, or a silver filter layer. Films may also have absorber dyes to improve sharpness and reduce halation, at a cost of some speed.
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#17 Scott Larson

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Posted 17 August 2006 - 03:29 PM

I think one of the only film without an anti-halation backing now is b+w infrared.

Yes, Kodak High Speed Infrared Film

Since it's also sensitive to blue light, some photographers skip its infrared characterics and shoot it through blue filters. This can give photos a dreamy look similar to 19th century photos that is caused at least partially by the halation. Some shots look like they had been shot through uncoated lenses but I think that's more likely an effect of the film.
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#18 Nick Mulder

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Posted 19 September 2006 - 02:42 AM

B&W Negative for both still and movie use actually is made on a GREY base for that purpose. Some of the OLD ADOX films actually had a dye layer on the back of the film which bleached itself out when it hit the chemicals. I rember the first time I tried a roll in Rodinal, and poored out developer that was almost black-purple from the dyes.
I suspect that some films may use the same special dye technique in the lowest layer of the emulsion. clearing by the time it emerges from the fixer.

The silver layer would only work for color negative or reversal films, where in both cases the silver layer would be removed.



yep, I remember my first roll of Ilford Pan F souped in Rodinal - I thought I was pouring my images down the drain :D
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