Projecting old Kodachromes

Roger Cole · Oct 16, 2013

Kodak is notoriously conservative. Someone may have used a very sensitive instrument and found they could find the first detectable change after one minute in front of a carbon arc lamp or something, and made the recommendation.

StoneNYC · Oct 16, 2013

Roger Cole said:
Kodak is notoriously conservative. Someone may have used a very sensitive instrument and found they could find the first detectable change after one minute in front of a carbon arc lamp or something, and made the recommendation.

Mmmm carbon arc lamp!! I'm told by many a gaffer on movie sets they still use them every now and then, but I have yet to actually have the privilege of seeing one in action.

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Tom1956 · Oct 16, 2013

Or they could have discovered 1 minute may not be noticeable at that time, but sets in motion a much faster timetable for future fading.

winger · Oct 16, 2013

I know wikipedia isn't the best place to get the most accurate info, but...

When stored in darkness, Kodachrome's long-term stability under suitable conditions is superior to other types of color film. Images on Kodachrome slides over fifty years old retain accurate color and density. It has been calculated that the yellow dye, the least stable, would suffer a 20% loss of dye in 185 years.[23] This is because developed Kodachrome does not retain unused color couplers. However, Kodachrome's color stability under bright light, for example during projection, is inferior to substantive slide films. Kodachrome's fade time under projection is about one hour, compared to Fujichrome's two and a half hours.[24]

I couldn't get to the Wilhelm Institute paper that's in the references, though.

And I was initially more worried about the possibility of the slide catching on fire or melting while being projected - which is probably from somewhere in my quite active imagination anyway.

Yeah, Roger's suggestion a few posts up is likely it.

lxdude · Oct 16, 2013

Bethe, it might not be from your imagination. Movie film will quickly melt if it gets stuck in the gate. It takes a lot of heat, but at 24 frames per second, not for long.

ME Super · Oct 16, 2013

Movie projectors put out lots more heat than the average slide projector, which has a fan to whisk the heat away. I wouldn't use a slide projector with a broken hot mirror, which reflects IR but lets visible light pass, but 1 minute in front of the bulb shouldn't affect it too much. An hour, on the other hand, according to the Wilhelm Institute, would fade Kodachrome, where the Ektachromes and Fujichromes can spend 2.5-3 hours in the projector before they get a similar amount of fading.

ME Super · Oct 16, 2013

StoneNYC said:
I left a Kodachrome slide in my window for a whole year I see the affects of light on it, it seems fine... It's a direct sun window getting hit at least half the day.

I'm not saying that a projector won't do damage just surprised the bulb would after only 1 minute.

Also I would agree that duplicating it would probably be the smart move

Dwayne's Photo still does it I believe.

Yes, Dwayne's still does it. A duplicate from a 35mm slide is US 50 cents, but from a negative or a digital file is US$1.10. I just got some back from them yesterday that I'd scanned negatives of and sent to them. B&W slides from Rollei IR400S look pretty cool

AgX · Oct 17, 2013

ME Super said:
I wouldn't use a slide projector with a broken hot mirror, which reflects IR but lets visible light pass,...

I assume typically it is the other way round, with visible light being reflected. Anyway, a good designed slide projector cools by means of air stream the lamp, the lamp housing, the IR filter in the lighting beam and the slide itself.

fotch · Oct 17, 2013

So lets see, they last forever if you don't look at them with light. However, its OK to look at them with the lights off.:confused:

ME Super · Oct 17, 2013

AgX said:
I assume typically it is the other way round, with visible light being reflected. Anyway, a good designed slide projector cools by means of air stream the lamp, the lamp housing, the IR filter in the lighting beam and the slide itself.

From wikipedia (http://en.wikipedia.org/wiki/Hot_mirror): "A hot mirror is a specialized dielectric mirror, a dichroic filter, often employed to protect optical systems by reflecting infrared light back into a light source, while allowing visible light to pass." A cold mirror, according to wikipedia (http://en.wikipedia.org/wiki/Cold_mirror), "A cold mirror is a specialized dielectric mirror, a dichroic filter, that reflects the entire visible light spectrum while very efficiently transmitting infrared wavelengths."

I looked it up after I saw your post because I thought you were right and I had it backward. No biggie 'cause I'm not designing, building, or repairing slide projectors, just using them.

AgX · Oct 17, 2013

You are right, but to my understanding projectors typically use cold mirrors to drain the majority of IR-Radiation at the lamp stage.

Hot mirrors are used to even highten the temperature of the filament in a halogen lamp to make it more effective.

Bill Burk · Oct 17, 2013

winger said:
... I was initially more worried about the possibility of the slide catching on fire or melting while being projected - which is probably from somewhere in my quite active imagination anyway...

You might have seen melting movie film, because the small frames needed such intense light to fill a screen that if you didn't keep the film moving (if it got stuck) most projectors would melt the film.

Doesn't happen much with 35mm.

But, I had a Bell & Howell Slide Cube projector which melted one of my favorite slides. The darn thing was engineered only for square corner cardboard mounts and had real trouble feeding the later round-corner mounts. But it ran hotter than any other projector.

Still, I'd rather show for 20 seconds - a real slide on a real screen... and have that experience. Than miss out because I was worried about ruining the slide.

StoneNYC · Oct 18, 2013

ME Super said:
Yes, Dwayne's still does it. A duplicate from a 35mm slide is US 50 cents, but from a negative or a digital file is US$1.10. I just got some back from them yesterday that I'd scanned negatives of and sent to them. B&W slides from Rollei IR400S look pretty cool

I'm confused, what's Rollei IR400s? I've seen Rollei Retro 400s and Rollei IR400

But not combined, and the internet doesn't seem to give me an answer... Thanks.

Wonder why they charge more? I hope they aren't personally scanning and then using their scan to project into the new slide, because their scans are horrible LOL

Their prints are beautiful if you send them files digitally, but unless they've improved, the last Kodachrome slide I got scanned from them (2010) was just horrible.

Thanks.

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AgX · Oct 18, 2013

StoneNYC said:
I'm confused, what's Rollei IR400s? I've seen Rollei Retro 400s and Rollei IR400

But not combined, and the internet doesn't seem to give me an answer...

Maco themselves started quite some confusion in the past by seemingly labelling the same Agfa 400 ASA film differrently for their own Rollei range. They even produced a Rollei datasheet that contained figures/graphics from two different Agfa data-sheets.

But so far no "IR 400S" designation turned up...

(Long ago Agfa made a 400 ASA film on PET base but without IR-sensitization.)

ME Super · Oct 18, 2013

The "S" in IR400S denotes a synthetic base. I'm thinking that the Retro 400S and the IR400S and the IR400 are all the same film. Incidentally, I'm told that the Rollei Retro 80s also has a bit of IR sensitivity - out to 750nm, where I think the IR400 goes out to 820nm before the sensitivity drops to zero.

I got a slide of the IR negative through a hybrid process which is verboten on here. DR5chrome can reversal process this film, but I haven't had the nerve to send it to them yet as they're saying they only see partial IR effects, where it looks like I'm getting full IR effects with my film by using a cheap Chinese 720nm filter and sending it through a non-reversal process.

StoneNYC · Oct 18, 2013

ME Super said:
The "S" in IR400S denotes a synthetic base. I'm thinking that the Retro 400S and the IR400S and the IR400 are all the same film. Incidentally, I'm told that the Rollei Retro 80s also has a bit of IR sensitivity - out to 750nm, where I think the IR400 goes out to 820nm before the sensitivity drops to zero.

I got a slide of the IR negative through a hybrid process which is verboten on here. DR5chrome can reversal process this film, but I haven't had the nerve to send it to them yet as they're saying they only see partial IR effects, where it looks like I'm getting full IR effects with my film by using a cheap Chinese 720nm filter and sending it through a non-reversal process.

Thanks hmm anyone want to test all 3 on the same image and see if they are all IR sensitive? I really wish, ESPECIALLY for sheet film, that companies would sell a "variety pack" with like 4-6 of each type of sheet they produced so you could test them all, or even a variety pack for roll film... I never understood why this wasn't a common thing...

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ME Super · Oct 19, 2013

StoneNYC said:
Wonder why they charge more? I hope they aren't personally scanning and then using their scan to project into the new slide, because their scans are horrible LOL

I don't know, as I sent them files on a CD, and the slides turned out just fine. I do know that direct from slide is 50 cents, while from the other sources it's $1.10. Judging by the code along the edges of the film, they're using Ektachrome/Elite Chrome for their dupes. The code in the rebate is EB-3.

Projecting old Kodachromes

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