8mm Forum: Lines

This is topic Lines in forum 8mm Forum at 8mm Forum.

To visit this topic, use this URL:
https://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=010884

Posted by Daniel Macarone (Member # 5102) on August 11, 2016, 10:35 AM:

This was mentioned a little in another thread, but I've always wanted a thorough understanding of this- I have been curious what causes the different kinds of scratches (black, green, clear) on film and how they can be avoided. I understand bad rollers scratch film, so besides that, I'd love to hear knowledgeable explanations. Can you identify the type of scratch based on its appearance?

Posted by Andrew Woodcock (Member # 3260) on August 11, 2016, 10:51 AM:

I dare not answer this one in full Daniel for fear of being struck off! [Big Grin]

What i will say is if a line or mark has a green appearance and is permanent no matter how or what you clean the film with, it is an emulsion scratch caused to the emulsion side of a print. (The inside layer or the one facing the projector lamp)

Black lines are generally base scratches caused to the base side of a film where there is no actual image printed to it.
These can usually be made invisible by using film cleaners.

Opaque lines can often be from the actual negative used when the film was printed and as such, they are also permanent.

for advice on how to avoid permanent scratches from our machines, hygiene has a big part to play in it as well as inherent design and the machines well being.

Posted by Tom Photiou (Member # 130) on August 11, 2016, 11:10 AM:

Only thing i can say on this in a nutshell is this,
low end range projectors will almost certainly cause scratches,
Many people do clean there film paths but often do not clean the rollers and this will cause problems,
projectors that are not looked after are a huge cause,
Most unfortunately now we are at an age where many machines, (good ones and bad ones), no longer have any spares available for them, generally film guides and rollers. Many do not ever get serviced so oils turns gooey and rollers often stop turning so film simply rubs over them and if there is dirt on them that will cause damage.
Have to say, those heavy green emulsion scratches are beyond me, i have no idea what state a machine has to be in to cause these BUT, when an old Eumig we had was returned under warranty the shop gave us a newish B&H filmosound projector. I hated this machine especially when i put a brand new 400ft film through it only to do it a second time and this machine put a green scratch all the way through it, i have never touched a B&H ever since,(except 16mm as these are very good).
Some people say Elmo 1200HD's cause black lines to the right, and i am sure they do, as for us in 37 years of collecting we have owned 3 of these machines, and out of thousands of hours of viewing with well in excess of 400 films and 150 odd ad reels/trailers our projectors appear to have only put a single light black line to far right on two short films.
I do however have an extensive supply of guides, i look after my machines like teeth, i am always cleaning them and inspecting them and at the ages they are now this is a must for everyone.
Looking At some of projectors that come up on flea bay i have to say i would not run my films on 90% of them. [Wink]

Posted by Andrew Woodcock (Member # 3260) on August 11, 2016, 11:18 AM:

Just one exclusion to the rule above Tom that I am aware of,in my time of collecting...
The Agfa LS(2) (when in good working order of course!).

Very very kind to film and very reasonably priced now.
Not much in the way of features but a fine mechanism to place any super 8mm film through. [Wink]

I am sure there are others, but none that I have ever used in the budget category.

Posted by Daniel Macarone (Member # 5102) on August 11, 2016, 01:09 PM:

Can a black line be caused by a bent reel scraping the side of film? If so, how hard is the reel allowed to scrape it?

Posted by Andrew Woodcock (Member # 3260) on August 11, 2016, 01:18 PM:

Reel wobble and scraping in itself is unlikely to cause scratching, but what it does cause is the film to run out of alignment to things such as initial guide rollers etc.

When this happens, a film can ride up over the machined tracks in such rollers into places it shouldn't.

Once this happens it is highly likely the film is not running along its intended smooth surfaces so then of course lines, black or otherwise, can of course appear.

It really does pay dividends to always try to use quality spools for both your films and take up duties.

Posted by Daniel Macarone (Member # 5102) on August 11, 2016, 01:57 PM:

Thanks for your answers.

Posted by Andrew Woodcock (Member # 3260) on August 11, 2016, 02:31 PM:

You're welcome Daniel. [Smile]

Posted by Tom Photiou (Member # 130) on August 11, 2016, 03:13 PM:

Must admit there reel wobble is so annoying when all you can here is the creak and scrape of the film being squeezed in the reel, time to change that one and dump it. [Wink]

One more exception Andy, The eumig range, relatively low prices and always good to film, the only problem is the reel size limit,even on the big ones. [Wink]

Posted by Andrew Woodcock (Member # 3260) on August 11, 2016, 03:50 PM:

I must admit Tom, first time around in the early 90's i did buy a Eumig D810 like this one reviewed on The Reel Image website here:

http://www.thereelimage.co.uk/archive/projectors/8mm/eumig/eumigsup8proj.shtml

It was a nice sturdy machine which worked reliably and produced very nice powerful sound. I recorded my Florida holiday soundtrack on it and it worked wonders!

However, it wasn't entirely innocent in the scratch department and it was always kept immaculately clean internally. [Confused]

It wasn't too bad, just not what you'd call 100%
Luckily the holiday footage went through unscathed but it did do a little damage to a few of the U8 prints I had back then as I recall.
Little Miss Marker springs to mind.

I've never had any mither from the last model they made though where any of this is concerned. Very gentle machine.

Posted by David Hardy (Member # 4628) on August 11, 2016, 04:53 PM:

Andrew and Tom have answered your question very well indeed but let me elaborate and give you my summary of some common causes of print scratching and the types of scratching

A : CLEANLINESS...All parts of the projector should be kept scrupulously clean, particularly the film path. Scratching the
main cause of emulsion or base-side damage , is usually caused by some extraneous matter coming up against film on its passage through the projector. These show up as continuous green or black
scratches on the print. They are known as "Tramline" scratches.
So always clean the gate and film path before and after projecting a reel of film no matter what length.
So in this case DIRT is the common enemy and cause of scratching.

B : MECHANICAL... Scratches can be caused due to wear and tear on the film mechanism and the sound head areas.
Here the main culprits are the guide rollers getting out of alignment with the sprockets and ridges on the rollers due to wear.
Also any tension springs and the bearings. So watch out for these and keep them lightly lubricated and don't let them dry out.
Also check those sprocket pad rollers or idlers are correctly spaced from the sprocket. Too little will cause rubbing to much will cause film run off and damage.
Clean and lube the sprocket shafts periodically.

Gate Tension : if not set correctly will not only cause picture judder but also cause some scratching.

Film Feed and Take Up tension : If not correct on the feed spool will not only lead to jerky film feed but could cause perforation damage but also puts slight strain an the film causing scratching.
Whereas incorrect take-up tension can cause strained perforations
and again cause scratching due to the strain.

C : FILM HANDLING ... Make sure the print is not rewound to slack. This can lead to scratching not only during projection
but also rewinding.
Make sure your rewind arms are perfectly aligned.
Rewind at moderate speed and slow up towards the end so the print does not flap.
Make sure there are no proud edges as this could damage the perforations if incorrectly handled.

D : TYPES OF SCRATCHES ...

(1)... TRAMLINE SCRATCHES are continuous straight scratches on
on either side of the film. Typically caused by dirt or faults
on the machine.

(2)... CINCH SCRATCHES are short lengthwise scratches caused by attempting to tighten a reel by pulling on the outside leader or tail. However they can also be caused by projecting a loosely wound film or poor rewinding.

(3)... CROSS ABRASIONS usually caused by the edge of a spool during rewinding. They are diagonal scratches that run from one edge to another on either side of the film.

(4)...RANDOM SHORT HORIZONTAL SCRATCHES caused by contact of the film with the rewind bench or worse still the floor.
So make sure you have a clean surface when making a splice or
joining those reel parts together when making up a show.

I hope this helps as general guide on how to avoid scratches and
some of the causes.

[Smile]

P.S. Throw out those buckled spools they are no good.

Posted by Andrew Woodcock (Member # 3260) on August 11, 2016, 04:57 PM:

With over 40 years in the business, this is obviously top professional advice here David thanks! [Smile]

Posted by David Hardy (Member # 4628) on August 11, 2016, 05:17 PM:

No problem guys you are all welcome.
I had to SCRATCH my head quite a bit to remember most of this.
[Big Grin]

Posted by Paul Browning (Member # 2715) on August 11, 2016, 06:14 PM:

well done David, that is it "in a nutshell", I can't see how anyone could summerise it so complete or add anything more. I will copy and paste to keep.

Posted by David Hardy (Member # 4628) on August 12, 2016, 03:06 AM:

Paul there are some more issues such as film rubbing marks but I
wanted to keep things as concise and general.
Thanks guys.
[Smile]

Posted by David Roberts (Member # 197) on August 12, 2016, 03:50 AM:

the problem I did have was pairs of small green emulsion scratches,one above the other,and lasting the entire film,
these happened below the gate,so by the time I realised, about a third of my films were ruined.

Posted by Tom Photiou (Member # 130) on August 12, 2016, 01:57 PM:

Great info there David, [Wink]

UBB.classic^TM 6.3.1.2