8mm Forum: Horizontal Lines on Screen?

This is topic Horizontal Lines on Screen? in forum General Yak at 8mm Forum.

To visit this topic, use this URL:
https://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=8;t=000765

Posted by Steve Klare (Member # 12) on February 02, 2008, 08:02 AM:

We went to see The Bucket List last night (highly recommended),

I noticed something odd which I've seen in other theatrical movies lately. There were scratches on the screen, but they were horizontal!

Could this be something to do with the film being on a platter and extracted laterally?

Other than that it makes no sense to me.

Posted by Maurice Leakey (Member # 916) on February 02, 2008, 09:38 AM:

Steve

I worked all my life as a 35mm projectionist and latterly used cake-stands (platters) and never experienced horizontal scratching. Film on platters whilst moving sideways actually goes through rollers in a vertical position (sideways vertical - if you see what I mean.) Green prints are always a problem with build up of new emulsion often clogging the gate and causing vertical scratches. In the old days gates were cleaned after every 2000' change-over, now its 15000'!

Scatching as you describe could possibly happen in the UK and other countries which still ship 2000' rolls on cores, if a roll is loosely wound and hardly fits into its can, a projectionist (God help him) might force it to fit, thus causing vertical (i.e. horizontal on screen) scratches.

This, however, is unlikely to happen in the USA as films are still shipped on 2000' spools, three to a six-sided transit case. At least, they were last time I was in the USA, some ten years ago at the Hollywood Galaxy.

However, this doesn't really answer your question and it would be interesting to hear from a US projectionist used to platters and their possible problems.

Maurice

Posted by Steve Klare (Member # 12) on February 02, 2008, 09:59 AM:

This is at least the second theater I've noticed it in.

I wasn't really surprised about the first one, since it's the local, budgety, sticky-floor kind of place, but last night was a much nicer theater.

Usually the scratches are on the right hand side of the screen, and down towards the bottom corner.

Most people just watch the movie. I watch the print!

-Funny story: We went in to see Bucket List, sat through the coming attractions and then the feature started. An off-camera character was trying to entice a kitten onto a glue board and record it with a camcorder. I thought "It must be Jack Nicholson. No character Morgan Freeman would ever play could ever do such a thing!". Only then did we realize we were in the wrong auditorium and seeing Untraceable. We beat a hasty exit and made it in time for the beginning of The Bucket List.

Posted by Bill Brandenstein (Member # 892) on February 04, 2008, 01:19 PM:

One of our local theaters has incredible equipment, but not always the care to run it well. So we recently ended up watching National Treasure with analog sound and horizontal green scratches (about 1 per foot, at regular intervals) for the entire show. No PTRs on this system either for the looks of things.

Afterwards, the manager just had a "oh well" attitude, because he's not the projectionist. Despicable.

What in a platter system could possibly mark the entire print in such a way?

Posted by Graham Ritchie (Member # 559) on February 05, 2008, 02:13 AM:

Hi Bill
Platters and projectors don't scratch films, only poor threading, might be the film is not on a roller properly, regarding "National Treasure" I am surprised the cinema is running it only in analog even with a faulty Dolby Digital soundtrack. Where I work we also have the option of DTS as well, analog is fine for a certain type of film eg "Atonement" but films that have plenty of action Digital is a must, a few years ago we had the manager of a modern multi-plex sitting in one of our cinemas and was impressed with our sound system, when we later had a chat I mentioned that it was because each of the 750 watt "per channel" amps is connected to quality speakers, the results when we crank it up is impressive!

Graham. [Smile]

Posted by Maurice Leakey (Member # 916) on February 05, 2008, 04:11 AM:

We were running a Vic 8 fed to/from a Christie 3-platter and scratched a film.

To those not familiar with these, the film is fed from the centre and passes through two plastic guides (they do not rotate). The platters are rim driven by a rubber roller under the platter which it is driving.

In a multiplex we would check each screen every ten minutes or so to ensure everyting was running OK. In this instance an awful deep yellow scratch was visible on screen. It hadn't been there on a previous run. An aerosol air spray was applied around the gate area in the hope that someting might get dislodged (gates are cleaned after each run.) This didn't help as an examination of the moving film showed that the scratch was there before the gate.

Then the trouble was spotted. The film was feeding from the bottom platter, and back to the one above it (the middle platter). The rubber roller (obviously past its sale date) was shedding bits of rubber downwards on to the feed roll. The movement of the film had brought a lump of rubber and lodged it between the two guides. This was causing the film to be scratched.

The rubber roller was replaced. It's not always possible to do repair jobs when running single manning, but by using the top and bottom platters the middle one could be attended to.

I still prefer the days of two projectors doing 20-minute change-overs!

Maurice

Posted by Graham Ritchie (Member # 559) on February 06, 2008, 02:22 AM:

Maurice
Thanks for the tip regarding the Christie platter the motor drives [Eek!]

although still intact looked like they had seen better days so will order 5 next week

We use a five deck Christie in cinema 3 which is fitted out with the "Kinoton" we use the 5 decks a lot as film can also run to or from the platter to other cinemas while other decks are being used for this projector and run up to nine different features in one day on the three screens.

Those vertical posts you mention, I check and rotate every so often when the wear gets a bit much, well Maurice thanks again, the Super8 forum is indeed a handy place for all kinds of information.

Graham. [Smile]

Posted by Maurice Leakey (Member # 916) on February 06, 2008, 03:16 AM:

Graham

Sounds that you have some busy days.

Now that you have posted those superb photos, readers of the Forum can see that the double "posts" being curved only normally touch the film at its edges near the perfs, the picture area being clear of any contact.

It was only that this lump of rubber got caught between the "posts" and the film was dragged past it causing the scratching.

Maurice

Posted by Hugh McCullough (Member # 696) on February 06, 2008, 06:09 AM:

Scratches can be caused by either the emulsion rubbing against the edge of a badly bent spool, this should be thrown out, or a "Projectionist", and I use the term loosely, holding the film at such an acute angle as to allow the emulsion to, again, come in contact with the spool edge.

This was a common problem in the changeover days when trying to train a person to check the film between their fingers when rewinding, and at the same time keep the edge of the film flat on the spool edge so that there was no uneven winding.
This was a little tricky until your fingers built up a resistance to the heat caused by the friction between fingers, and film.

Posted by Maurice Leakey (Member # 916) on February 06, 2008, 09:10 AM:

Hugh

The Rigby Premier rewinders used to have a spring tensioner on the feed spool arm to provide sufficient "drag" to ensure an even take up back to the supply spool.

The only use of fingers was to locate a join, and if so, to stop and check to see if it was still OK.

Maurice

Posted by Hugh McCullough (Member # 696) on February 06, 2008, 11:28 AM:

Yes Maurice, I know that all rewinders have a tension spring to supply a certain amount of "drag".

The only use of fingers is to not only to locate a splice, but also any damaged sprocket holes, and to help the film run onto the spool in an even manner.

What causes scratches is if the film is twisted by the fingers so that the emulsion rubs against the rim of the spool.

You state that you have been a 35mm projectionist all your life.
How long is that?

I have been a professional projectionist for 49 years, did a four year apprenticeship, sadly these are no longer in existence. Have run 16mm, 17.5mm, 35mm, and 70mm, both married and unmarried prints.

Posted by Maurice Leakey (Member # 916) on February 06, 2008, 12:30 PM:

Hugh

I was trained by CMA in 1952.

Maurice

Posted by Hugh McCullough (Member # 696) on February 06, 2008, 04:45 PM:

So, Maurice, you outrank me. Nice to know that there are some more oldtimers out there.

I have a cinema website, (www.cinephoto.co.uk) and am always on the look out for photographs of boxes, projectors, and cinemas to place on it.
Have you, or any one else, any cinema related photos that might be used on the site?
I do hope so.
Photographs from outside the UK are most welcome.

By the way the photos can be of any gauge equipment.

Hugh.

Posted by Graham Ritchie (Member # 559) on February 06, 2008, 09:17 PM:

Hugh
Your web site is very good, sadly out here many cinemas like the Cinerama have all gone, what is worse there is no known photo record of many of them, your projectionist survival kit was interesting, a little bit different to the one Peter Sellers used in "The Smallest Show On Earth" [Big Grin]

here is a couple of photos of my version of a wrap-detector.

I made this one for the "Kinoton" this is the MK1 model more to follow the MK2 for the Bauer and Simplex having a wrap-detector on the platter in this cinema is not practical due to number of films coming and going in all directions, it protects the projector from damage that might occur using polyester film and is fitted right next to the projector, took half a day to make it in the garage.

In the event of the film coming under tension, it pulls the lower assy out of a spring loaded latch, at the same time the micro-switch on the left, which is wired to the computor shuts the projector down, most of this stuff was bought from a local hardware and aluminium supplier, except for the rollers and switch.

allowing for a projector run down period this is were the film stops, with no strain to the film and most importantly no damage or excess load to the projector, I have tested it out and it works great, I wonder if I should go into business?. [Wink]

Graham.

Posted by Steve Klare (Member # 12) on February 06, 2008, 09:24 PM:

I had no idea how many professional projectionists there are around here!

So, where did the horizontal scratches come from then?

Posted by Graham Ritchie (Member # 559) on February 06, 2008, 10:01 PM:

Hi Steve
I certainly don't claim to be a professional projectionist just a humble one [Big Grin]

I only got into it because no one else wanted to do it, in fact when I turned up the projectionist gave me a crash course, I still remember me shouting after him as he rushed down the stairs to go on his holiday,... what if I have problems,... the reply came back you will figure it out [Roll Eyes]

I have never seen anyone in such a hurry to escape, that night I did my first interlock of "Pearl Harbour" 1200 people [Eek!]

with much relief the night went well, it was a case of sink or swim.

Regarding those horizontal scratches [Roll Eyes]

sorry haven't a clue. [Smile]

Regards Graham. [Smile]

Posted by Patrick Walsh (Member # 637) on February 07, 2008, 02:30 AM:

Graham's wrap dector is very good and yes would recomend making / selling more!
speaking of platter scratches those new films at work 2 of the 3 have platter scratches, one (Priceless) so bad made up other copy to run, big green scratches down the centre and horizontal scratces all the way through comming almost half way across the screen, the other (death at a funeral) has minor markings all the way through on side of image.
There must be many ways films can become scratched either using reel to reel of a platter system, no system is without its problems but if it has been installed and set up right and has been looked after and the machine cleaned every thread-up and the film path checked you should not have any problems.
all films do get a bit knocked around about after a while especially 35mm, going from one theatre to the next, being run on platters , reel to reel, towers etc.
Hugh your website is very good, nice to see some images of a Kalee 12, I used to have one of those here at home, using a very old NZ made "Realtone" soundhead that mounted out the front of the head just beneth the lower sprocket, looked like a piston head from a motor cycle engine, ran very well but had to sell as I was in short supply of the old $
Now have a Ernemann II machine from 1920s Germany a workhorse and some are stll in commercial use today, they were front shutter and when scope came out you could buy a conversion kit to change them to a drum shutter so a cinemascope lens could hang out the front.
[Smile]

Pat

Posted by David Kilderry (Member # 549) on February 07, 2008, 07:31 AM:

Steve there are a number of ways horizontal scratches can occur. If they are consistant all the way through the print then it is most likely a mis-thread on the take-up platter, this is where the tension is greatest. For a horizontal scratch to occur the film must come into contact with a roller or disc spinning across it. A missed roller on the approch to the take-up platter can drag the film over its edge and cause those scratches.

The scratches can also occur during make-up, if the film is dragged against the spinning edge of a spool, espcially a metal one it will cause these scratches. They ones are generally less consistant as the person winding the film will vary their bad winding technique!

It can also occur making the print up onto the platter from the 6,000 ft spools. Again the edge of the spinning platter can cause it.

Did the scratches curl up slightly at one side? Were they black or green?

It is not a common scratch, but made much more common with the introduction of platters over the last 30 years.

You will find a great deal more info. on the big brother film-tech.com forum.

David

Posted by Jean-Marc Toussaint (Member # 270) on February 07, 2008, 08:55 AM:

Way to go Graham! Excellent system. I was offered an actual Cinemeccanica poly-safety assay last week for a very high price. I turned it down cause I had noticed that it was in essence no more a reinforced drawer mecanism with rollers and a microswitch. Your photos prove me right...
[Big Grin]

Posted by Hugh McCullough (Member # 696) on February 07, 2008, 11:42 AM:

Graham, and Patrick.
Please check your email.
Thank you.
Hugh.

Posted by Patrick Walsh (Member # 637) on February 07, 2008, 02:16 PM:

Hi Hugh
Thanks for the email have replyed.
Patrick

Posted by Bill Brandenstein (Member # 892) on February 09, 2008, 11:00 AM:

My vote goes to David's conjecture - mis-threading of a roller on the takeup platter. The markings were consistent on every part of the show - ads, trailers, feature - and ranged from light black to intermittantly slightly green. So not as likely to have occurred when building up the show, or from flange binding (too consistent, too frequent in this case). The print was first-run and about 2 weeks old.

Graham, I can't explain the lack of DTS backup. But this is part of what makes me so frustrated, is the apparent lack of care/concern. Perhaps competence too, but other times this place has been spectacular. Ratatouille was amazing (and loud -- you should have heard the thunder clap. We jaded moviegoers came out of our seats) with a picture quality that could send digital cinema packing at full speed down the street (flawless).

Maurice, Graham, Hugh, Patrick, and David (am I missing anyone else?): this has been a fascinating read. Thank you!

UBB.classic^TM 6.3.1.2