This is topic SMPTE vs. the real world in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Brad Miller (Member # 2) on 06-05-1999, 04:07 PM:
So the standard SMPTE PA-35 (RP-40) test film is supposed to be the standard "reference" test film. Ok, fine. That being said, can anyone explain why EVERY film is then printed "out of frame" when compared to the PA-35 loop??? The only film I've ever found to match is the analog THX Broadway trailer. But again, if you adjust your framing for perfect SMPTE specs and perfect "blue box" on the THX, the rest of your presentation will be low of center in the frame.
Anyone else notice this? Any theories?
Posted by Joe Redifer (Member # 3) on 06-05-1999, 04:33 PM:
I have noticed this. I went around and adjusted all of my framing to be perfect, and then I locked the knobs down so that they would never move. (Threading out of frame at my place is a big no-no). Then my senior tech comes in one day and for some odd reason we were running RP-40 and he says "That's too high, it needs to come down." So for fun I unlocked the framing knob and moved it down. Of course when the movie came on, it was seriously too low! The THX Broadway matches RP-40 standards and so dos the Mann Theatres Policy trailer (in scope, anyway). Just adjust framing with a good green band (make a loop) -- but remember, all green bands are NOT created equal, so make sure you have a good one!
Posted by Brian Paymer (Member # 57) on 06-20-1999, 01:03 AM:
I have noticed this myself. I don't have THX trailers but I just figured I had a bad batch of SMPTE test loop.
Posted by Brad Miller (Member # 2) on 07-11-1999, 03:08 PM:
Here's another idea. How about printing several feet of the SMPTE PA35 test film on the head of every feature film? That way we can see just how unstable current polyestar stocks and film printing is! I can run a loop of PA35 film on my Century JJ and the picture is as steady as a slide, but when I put some actual film (Deluxe labs in California is the worst) the picture bobs and weaves. This is magnified even more on a Christie projector, where there is bobbing and weaving on the PA35 alone.
Interestingly though, I can take an older film dating back to the 70s and 80s and they play ROCK SOLID!
Where's the quality control nowadays? Anyone else notice this? You can identify the Deluxe CA prints by the slashes through the title on the tail leader. Technicolor labs print the title in big block letters. Deluxe in Canada actually prints "made in Canada" on their tails.
Posted by Christopher Seo (Member # 7) on 07-11-1999, 05:31 PM:
I take it the test film is also polyester. But how can a lab's processing contribute to a print that runs unsteadily? How much of it is the fault of the manufacturer of the stock? Unfortunately I have never seen a steady picture on the brand new Simplexes we use. Shaking on the THX trailers is especially noticeable, but what that suggests I don't know...
Posted by Brad Miller (Member # 2) on 07-11-1999, 05:46 PM:
Check it out for yourself. Locate a Deluxe CA print and compare it with a Technicolor print. You will see the difference.Just make sure you compare flat vs. flat or scope vs. scope. Flat movies will always shake worse due to the larger blowup required to fill the screen.
Posted by Gordon McLeod (Member # 33) on 07-16-1999, 06:07 PM:
Printing speed and slippage between the neg and print will create an unsteady print
The faster the printing speed the greater the jitter
Posted by Christopher Seo (Member # 7) on 07-17-1999, 07:06 AM:
Ah, I see. So what happens is that Kodak gives the polyester base its characteristic unsteadiness, Deluxe creates unsteadiness in the alignment of the printed images themselves, and the result is a pretty bad image.
Posted by Gordon McLeod (Member # 33) on 07-17-1999, 11:25 AM:
The estar base in itself isn't unsteady it is the fact that most trap assemblies can't hold it steady. This hasn't been a problem din studio's and on most european projectors like ernaman and kinotone as there gate/traps have either velvet or delrin rails or bands
Being thinner it is also more prone to heat flutter than triacetate also the emulsion doesn't stick as well to it
The bottom line is estar is here to stay so why can't northamerican projector manufacturers designing around it. They are on the end of the chain not the other way around. E7's Motiographs and Century C's seam to have no problems with it, so I think it is probably the economics of making cheaper projectors in NorthAmerica that is at fault
Posted by Brad Miller (Member # 2) on 07-17-1999, 04:31 PM:
The biggest problem with Estar base films is the curl. That's pretty much it.Take a foot long strip of film. Lay it down on a flat surface emulsion down. See what happens? Only the edges of the film come into contact with the surface and the picture is arched upward. This is a "base curl". All prints before the switch to polyestar stock had an emulsion curl to them. I spoke to a gentleman at Deluxe a few years back about this and in the simplest words, this is caused during the drying process of manufacture. He said it COULD be done the other way and he didn't know the reasons as to why polyestar film was done in that fashion. He seemed knowledgeable, but not interested in changing.
Also, let's say you have a film with a base curl. Winding it onto a reel emulsion in (so the base side is outward) will exaggerate this and make the film run harder and be less pliable, because the more curl there is to the film, the stiffer it will be. If the same film is wound onto a reel emulsion out, it will actually flatten out the film, making it run smoother. This is why I always rant on people who run soundtrack down on platters. Before the introduction of Estar films this could be done, as triacetate stock was pretty forgiving. But, the soundtrack should always be wound up with polyestar films to prevent this from curling more. As for changeover theaters, I modify my takeup belts with an "S" so both reels spin counter-clockwise/emulsion out.
I have ran tests with running polyestar films backwards (to simulate an emulsion curl) and even a Christie projector runs them nicely.
Thus, Gordon is right, it isn't the Estar stock which is at fault. It is the labs for processing it with a base curl.
Posted by Brian Paymer (Member # 57) on 07-18-1999, 03:33 PM:
I tried running a trailer backwards. It wasn't night and day, but it definitely was steadier backwards and upside down. The projector ran quieter too.It figures Kodak would recommend to wind prints in a manner which will facilitate problems. Their advice on using PTRs isn't worth a dime, why should this be any different? I'm going to take a print and wind it soundtrack down to see how quickly the base tightens up.