Film-Tech Forum ARCHIVE: How do you identifiy test film

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Posted by Frank Dubrois (Member # 3042) on 06-30-2006, 07:20 PM:

We have a box of film (it LOOKS like some rolls of test film mixed with other film) that I cannot identify. They are all small rolls, unlabeled, unidentified. Some is all gold, some has a color that ranges from purple to white then back to purple. Some looks clear with a small border around each frame.

Is there a place that has photos of test film so I can identify this stuff? Is it of any use? Does anyone know just by my bad description what this film is used for? It may not even be test film, but that is the box I found it in...unfortunately, no labels or reference to it at all.

Thanks for any help.

Posted by Tim Reed (Member # 137) on 07-01-2006, 12:18 AM:

Leader stock, maybe? Is there a soundtrack? If so, is the waveform continuous/repetitive?

Posted by Frank Dubrois (Member # 3042) on 07-01-2006, 01:34 AM:

I saw no soundtracks at all. All this stuff is different looking too. The really weird one (the one that goes from purple then fades to white then back to purple) is the only one I've ever seen before, but I dont know what it is for.

Posted by Tim Reed (Member # 137) on 07-01-2006, 02:23 AM:

That sounds like lightstruck leader to me... worthless.

Posted by Stephen Furley (Member # 1277) on 07-01-2006, 10:18 AM:

Anybody have any idea what this is?

There was a couple of metres of it attched to the head of each reel of a print that I received recently.

Posted by Frank Dubrois (Member # 3042) on 07-01-2006, 01:19 PM:

I wonder if this box labeled test film is actually just a bunch of junk that somebody just didnt know what it was. Like that strip above. A whole box of crap.

Posted by Mark Gulbrandsen (Member # 72) on 07-01-2006, 07:25 PM:

Frank,

When we are all done training you in this art where do I send my part of bill for all of my advice that has been thrown in to these threads? You just don't seem to be able to figure anything out for yourself... do you?

Thanks in advance for your billing address!

Mark

Posted by Phil Hill (Member # 371) on 07-01-2006, 07:28 PM:

Like Stephen, I too would like to know what that film is for...it appears to only have DD and optical tone burst sound tracks.

Posted by Brad Miller (Member # 2) on 07-01-2006, 07:43 PM:

Guys, lighten up. I may be missing something, but the guy is trying to learn and it seems all he gets in response is senseless bashing.

If you can't or don't want to help him, please do not reply.

Posted by Mike Blakesley (Member # 26) on 07-01-2006, 09:00 PM:

quote: Frank Dubrois
I wonder if this box labeled test film is actually just a bunch of junk that somebody just didnt know what it was. Like that strip above.

Maybe they called it "test film" meaning it was for practice, like practice threading or splicing.

Posted by Richard Hamilton (Member # 321) on 07-01-2006, 09:02 PM:

Frank,
can you post any pictures of the film? Then we can determine if it is junk or really test film.

Brad,
I apologized to Frank in another thread, but you locked and deleted that whole thread. "I hate to be Frank but.." Yes, I have made some smartass comments towards Frank, but that is just my nature because of his comments in one thread. I have never met him, and probably never will, but I will offer any information that he or any one else asks for as long as I am confident I know the correct answer.

As far as my smartass comments go, I can take them as well as give them. When Joe R. said I was a female and had no male genitelia, I laughed my ass off and told him he won that round.

Frank, there is a vast amount of info on this site. Ask and learn as much as you can! I have walked into too many booths where the people don't know shit and dont care. I have also been in booths where the head projectionists likes to "tweak" too many things because he thinks he already knows it all, and is trying to be helpful, but in reality screws things up.

Rick

Posted by Tim Reed (Member # 137) on 07-01-2006, 11:31 PM:

quote: Phil Hill
I too would like to know what that film is for

Looks like someone was testing the light valve ribbons for maximum excursions. [Confused]

Just a guess. [Wink]

Posted by Monte L Fullmer (Member # 2797) on 07-02-2006, 01:43 AM:

Yea..got a bunch of these sound test strips as well.. on front of TECH prints that come in where the head leads were missing (since I get used prints for a discount house). Thus, I kept these for good sound loops of sorts... - Monte

Posted by Charles Greenlee (Member # 3856) on 07-02-2006, 02:01 AM:

I was guessing a sound test loop too, maybe dolby tones. But that wouldn't have had the DD track, and if I remember correctly, the wave isn't as simple as that. But it is a mono test track.

Posted by Stephen Furley (Member # 1277) on 07-02-2006, 06:18 AM:

quote: Charles Greenlee
I was guessing a sound test loop too, maybe dolby tones. But that wouldn't have had the DD track

Interesting you should say that; some new Dolby tone that arrived at the end of last year does have a Dilby Digital track on it. I don't have any means of playing a digital track, so I can't tell if there is actually any audio on it, and, if there is, I don't know what sort of signal, or what possible use it could have.

quote:
Looks like someone was testing the light valve ribbons for maximum excursions. [Confused] Just a guess. [Wink]

Tim,

I was thinking along similar lines to you, i.e. that it was not a test film as in a film made for the purpose of testing something else, but rather a film that was the result of some sort of test, carried out at a lab, which when it had served its purpose was a convienient roll of junk leader. There were several lengths which were like the one I scanned, one which had some sort of tone on it, not Dolby tone, and one which started out as one, then had a few frames worth of just bias line, then changed to the other. It looks lohe they were all cut from the same roll, which had two different signals recorded on it, one after the other.

quote: Richard Hamilton
can you post any pictures of the film? Then we can determine if it is junk or really test film.

Good advice; it's much easier to tell what it is if we can see it.

Frank

If it's real test film, like buzz track, Cat. 69 T or P etc. then it will probably have some sort if identification printed in the picture area at regular intervals. Pa35 projector alignment film describes itself as such on each frame.

Why did Dolby change from the double sided Cat. 69 to separate 'P' abd 't' loops; was it just to sell twice as much film?

Posted by John Hawkinson (Member # 1135) on 07-02-2006, 07:16 AM:

Current 69-T has an SRD track. I had been under the impression that was true ever since 69 split into 69-T and 69-P, no?

--jhawk

Posted by Stephen Furley (Member # 1277) on 07-02-2006, 07:22 AM:

Possibly, but I never noticed it before this film arrived a few months ago.

Posted by Tommie Evans (Member # 2674) on 07-02-2006, 08:39 AM:

quote: Frank Dubrois
Some looks clear with a small border around each frame.

Could be threading Mylar, known as 'Clear Mylar', usually has a solid soundtrack though?

Posted by Louis Bornwasser (Member # 3063) on 07-02-2006, 09:48 AM:

Dolby stopped the "2-sided" cat 69 to improve yield. Too many times one side was good and the other not good. Louis

Posted by Frank Angel (Member # 248) on 07-02-2006, 04:46 PM:

Stephen's strip of film isn't all that odd, at lease not to me; I have seen this kind of sine wave modulation before on leader, my guess would be it was on foreign prints, although I don't recall if the stuff I saw also carried a digital track along side it. Since I save everything, I probably could find it if I took it in my head to look for month or two (but I won't).

Why does it seem so unusual? Perhaps it's just something a lab used to calibrate low end response or something. Betcha my subs would like to have a wack at it.

Posted by Sean McKinnon (Member # 612) on 07-02-2006, 11:06 PM:

The purpose of the SR*D track on the cat. 69T is because it is also used as the cat 150 loop for SR*D reader alignment with the DRAS software.

Posted by Charles Greenlee (Member # 3856) on 07-03-2006, 04:12 AM:

Oh, I've never had to mess with any of that. I've used bizz track to align my cells. And I've used Dolby Tone to balance them. We didn't have any other test loops, except some we made from old MPAA green band from old trailers. If it's clear, decent to adjust focus, and picture on screen alignment. I really liked the coke ad where the guy and girl are in the theare, it worked wonderful as a focus track. I'd focus in and out untill I could clearly see the pores of the guy's face. You can't beleive how many projectors that were supposedly focused, and looked focused from watching the trailers or feature, that'd I'd check behind with the coke ad, that were still very out of focus.

Posted by Frank Dubrois (Member # 3042) on 07-03-2006, 06:17 AM:

I was told that focusing to pre-show material was a bad thing. Wouldn't the coke ad qualify as pre-show?

Posted by Mike Blakesley (Member # 26) on 07-03-2006, 12:31 PM:

It's OK to focus on pre-show material as long as you focus again when the feature starts. (And preferably check focus again after every reel change, at least.)

Posted by John Hawkinson (Member # 1135) on 07-03-2006, 01:44 PM:

Fundamentally, it's not a good idea to focus with different material than what you care about the focus of.

Different film stock, different ages, different wear, differnet humidity -- all of these things can affect focus.

--jhawk

Posted by Brad Miller (Member # 2) on 07-03-2006, 03:37 PM:

quote: John Hawkinson
Different film stock, different ages, different wear, differnet humidity -- all of these things can affect focus.

...except on a Kinoton. I recently ran a bunch of short bits of film through a Kinoton that ranged from 2006 film stock all the way back into the 40s. The films were all in different degrees of health, some warped, curled, acetate, polyester, etc. Not one time did I see any need to touch the focus. [thumbsup]

Posted by John Hawkinson (Member # 1135) on 07-03-2006, 03:48 PM:

Brad, isn't this a function of the depth of focus of your lens?
I always do get confused on depth-of-field, depth-of-focus, etc., but one of these determines how precise you have to be with
your focus, yes?

--jhawk

Posted by Brad Miller (Member # 2) on 07-03-2006, 03:54 PM:

Yes that certainly does help, but more importantly the Kinoton's gate design is such that the emulsion side of the film is at a constant position, unlike most projectors where the base is against the fixed runners and the emulsion rides on tensioning bands of some sort. Does that make sense?

Posted by Frank Angel (Member # 248) on 07-03-2006, 04:30 PM:

quote:
Yes that certainly does help, but more importantly the Kinoton's gate design is such that the emulsion side of the film is at a constant position,

That's very interesting, but am trying to picture it. How does it do that? If the emulsion is swollen with humidity, what would keep it in the same plane as emulsion that is normal or thinner? unless the emulsion is pressed up against something like a piece of glass to always keep the emulsion surface always in the same plane?

Then again, John is right in that unless the optical system is at some extreme magnification, like a huge picture at a very short throw, modern lenses all have a great enough depth of field to focus well in front and in back of absolute zero focal point. That broad range should compensate for the slight variations normally found in emulsions and film curl.

We run old films all the time, many times mixing lots of different prints and never have any focus problems, in fact, you can rack the focus knob back and forth slightly and still keep perfect focus. On a 50ft screen at 100ft throw, we are not pushing lens optics to any extreme magnification and the only time I can recall ever having a focus problem was with two reels of PORGY AND BESS that had VS.

Even before we got our ISCOs, the Kollermorgans and Snap-lites could get a very good focus with ease, and once you were on the money, it would say in focus no matter what you ran thru the machine.

Posted by Brad Miller (Member # 2) on 07-03-2006, 05:05 PM:

quote: Frank Angel
unless the emulsion is pressed up against something like a piece of glass to always keep the emulsion surface always in the same plane?

Not glass, but you've got the right idea.

Posted by Louis Bornwasser (Member # 3063) on 07-03-2006, 06:44 PM:

As Brad says; if the emulsion in held in a constant plane, then thickness of the base shouldn't matter much. Though Kinotones have the best idea, Kelmar turrets hold the locked position to much higher tolerances than normal Century gates and it shows in better focus. Likewise, older Century curved gates (H-style) have better focus since the emulsion side is held constant. Louis

Posted by Charles Greenlee (Member # 3856) on 07-04-2006, 03:28 AM:

Well, to answer the question earlier, yes. It's preferred to focus on the feature. But since often it can be difficult to tell focus from the booth, and through a window that won't open (and our ushers seem completely incompetant in coaching me over the radio on the focus), I've been figureing out tricks to help compensate. The ad was of similar stock, and good condition. I would place it by the area of the projector, so it'd adopt a similar temperature and humidity as the feature film. I would also run it immediatly after the feature drops, OR run the projector manually untill the trap and gate are up to operating temps. This will hopefully make sure any flexing of the loop from heat in the gate, will be as close to what the feature will experience. It works rather well.
I chose that trailer because the guy's pores make a pattern of fine dots that will pop out clear where you're in focus, and this effect if visible from my window. I've checked this the hard way. I've set my focus normally, and then run dowstairs to view it from the auditorium, and you can tell it's not well focused. I'll run the loop, and focus, and run down stairs later during the feature, and it looks 100x more focused.
So with a planar gate like that, don't you experience, what I heard called, "breathing" of the film? Supposedly it's why we have curved gates now, to reduce the film flexing back and forth in the gate as it heats and cools. Supposed to look kind of like it's breathing.

Posted by Brad Miller (Member # 2) on 07-04-2006, 04:16 AM:

Charles, your practice poses a few problems. First, you are striking the xenon just to focus on. This is bad for the xenon and kills lamp life. Second, a film left in loop form will tend to take on a different curl than a film wound on a reel or platter. This affects focus. Third, that loop of film is getting blasted by the heat of the lamp over and over every few seconds, whereas the real film only gets hit once every few hours for an instant. As such your loop may be embossed, also affecting focus.

Just buy yourself a $30 pair of binoculars. [Wink]

Posted by Monte L Fullmer (Member # 2797) on 07-04-2006, 03:53 PM:

Yea, I even shoot people who strike up the bulb just to frame with since they are too lazy to put on enough framing leader to thread with.- Monte

Posted by Frank Dubrois (Member # 3042) on 07-04-2006, 04:43 PM:

quote: Charles Greenlee
I would also run it immediatly after the feature drops

You do that every show? We check focus all the time (when the feature is playing), but find that we really dont have to do much adjusting..definately not between every show.

Posted by Charles Greenlee (Member # 3856) on 07-04-2006, 09:19 PM:

Nope, don't do the loop every show. That'd be a pain. I don't normally strike the lamp every time I want to do a test, just in rare cases, actually I've only done it twice. Usually, I just get to the projector before it drops and thread the test loop in as soon as it's done, the lamp can stay on (manually) for that few seconds with the lamphouse shutter down, so no need to restrike after the automation would normally kill it. And the test loop is no smaller in Diameter than what your feature would be wound on the platter, I usually let it lay out on the unused platter for that screen during the show before I want to run it. As far as the heating issue with the film, yup, can't solve that one. Yeah, I should get some binocs, but the windows where I'm at now, open, allowing for an unobstructed view. Still would be handy to have some tho. I wonder if I could con...errr I mean convice the theatre to buy some for the booth.