Film-Tech Forum ARCHIVE: film scratches

This is topic film scratches in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Carmine Occhino (Member # 1699) on 07-08-2003, 10:47 PM:

On screen I notice "white specs" which appear intermittently through out projection. I think I read somewhere in this forum that this type of scratch is caused by the emulsion being rubbed off due to varying tensions. This has to be happening in the make-up process because I see it the first show. I dont think I'm causing it when I load the film to the 6000 ft reels but rather when I'm loading the film to the platter. If I let the film run to the platter it will bob up and down so I have been holding the reel flanges lightly to stop that , a tip which I got from this forum. This is when I actually started noticing these type of scratches. If this is the problem how can I stop this from happening? If it isn't the problem what is causing these scratches?
I assume dirt shows up as black specs?
How often to "standing scratches" occur from incorrect loop size?
What would cause black hair like scratches to show up on screen?

Posted by John Pytlak (Member # 331) on 07-08-2003, 10:54 PM:

White specks or scratches can also be due to dirt or cinches on the printing negative, known as "shadow image" dirt. Most labs use on-line PTR cleaning and off-line solvent cleaning, but sometimes dirt becomes embedded in the printing negative.

Look at the area of the print where you see the white "specks" with bright, specular reflected light (e.g., hold the print under a spotlight or in the projector beam). Do you see any physical digs or scratches? If not, the marks were printed in.

Posted by Carmine Occhino (Member # 1699) on 07-09-2003, 10:18 AM:

Thanks John I'll check it out.

Posted by Carmine Occhino (Member # 1699) on 07-15-2003, 08:56 PM:

I can't tell if it's shadow image dirt or if it's a scratch. How common is this shadow image dirt ?

Posted by Leo Enticknap (Member # 534) on 07-16-2003, 03:10 AM:

During my time as a projectionist, and ever since as an audience member I get the impression that negative dirt and scratching is an increasing problem, especially for mainstream titles with very large print runs.

Posted by Carmine Occhino (Member # 1699) on 07-16-2003, 06:08 AM:

That would make sense because I really don't remember making a deal of this in the past....or maybe I just wasn't looking hard enough at the screen [eyes]

Posted by John Pytlak (Member # 331) on 07-16-2003, 08:30 AM:

quote:
During my time as a projectionist, and ever since as an audience member I get the impression that negative dirt and scratching is an increasing problem, especially for mainstream titles with very large print runs.

Sorry, but I disagree!

In my career at Kodak, I have been very involved in projects to improve the cleanliness and quality of release prints. With Kodak VISION Color Print Film, Kodak has made significant investments in improving the formulation, slitting, and perforating of the print film itself, greatly improving the dirt level:

http://www.kodak.com/US/en/motion/products/lab/2383.shtml

Kodak VISION Color Intermediate Film 2242 used for making printing negatives now has a scratch-resistant conductive layer that greatly reduces the attraction of dirt during printing and resists scratching:

http://www.kodak.com/US/en/motion/products/lab/5242.shtml

Kodak has worked closely with the labs to improve the cleaniness of their operations, such as my SMPTE Presentation "Some Positive Ways to Handle Negative". One of my nicknames at Kodak is "Doctor Dirt". [Smile]

The labs themselves have made remarkable progress in improving cleanliness and reducing handling marks. Bi-directional and loop printing have greatly reduced the amount of negative handling, improving cleanliness even for long print runs. Labs routinely use on-line cleaning of both raw stock and printing negatives during printing, and quickly pull a negative for solvent cleaning if dirt levels build. Several new "state-of-the-art" release print labs have been built in the last few years, using the latest in printing, processing, and cleanliness technology.

Distributors often contract for "third party" inspections of outgoing print quality to supplement lab QC. These include the THX Theatre Alignment Program (TAP), Dolby Distributor Services (Ted Costas' group), LedJer Print Services, Kodak ScreenCheck, etc.:

http://www.thx.com/mod/techLib/pdf/labgrad.pdf

http://www.dolby.com/press/co_pr_0207_PrintChecking.html

http://www.ledjer.com/services.htm

http://www.kodak.com/US/en/motion/screencheck/

So I am keenly aware of dirt issues, and have them on my mind every time I go to the movies. Although I occasionally wince at the dirt/defect level on a particular production (usually seems to be an issue of a careless negative film cutter), overall, I find the overall quality of release prints to have improved remarkably compared to "the good old days" of triacetate prints, rem-jet, and Model C printers.

Posted by Chris Markiewicz (Member # 1415) on 07-16-2003, 01:33 PM:

Our print of Nowhere in Africa (#76) had random white specks throughout. The print was very clean; the specks were printed in.
Note to all: this print was water damaged on its way to us, there was standing water in the reel 5-8 can. The tails of reels 5 and 6 were sticking (shipped tail-out). A good soaking with F-G saved the print!