Conventional film/processor issue

[Macmann]

Any of you old-timers remember running film through the soup? We are seeing fine lines approximately .001" getting pinched up from time to time and the customer is rejecting them. My first thought was chemistry ratio or developer temp. It's hard to pin down and happens intermittently. Any ideas? We're exposing on a Barco Megasettter Plus and the processor is a Kodak Polychrome. Thanks.

 

[Repro_Pro]

If these are thin Black marks parallel to the direction of travel, they are likely caused by the heat generated when the moving film bends and rubs against rough spots on metal surfaces, such as deflectors etc.
A large sheet of 7 mil film is rather stiff and when its' emulsion rubs against metal surfaces that are not thoroughly clean - thin Black lines tend to appear.

 

[Macmann]

Repro_Pro I can see why you answered that way-my question is worded for shizzle. We are trying to hold .001" lines and they are pinching up on us occasionally. We are running 7 mil at 4000 dpi and the results are usually outstanding but we are having issues with about 5-10% of films. A buddy of mine who was a Kodak rep back in the 90's immediately blamed it on the chemistry possibly developer temp - I was just looking to pick the brains of the Print Planet experts.

 

[Repro_Pro]

OK, I see...
In my experience you need to rip and expose at a higher resolution to get well formed 1 mil lines.
Is 4000 dpi your maximum res?

 

[gsbatch]

Light leak. Laser intensity. Line voltage issues affecting processor speed. Pre-exposure of material from the factory. (That one nearly drove me over the edge.)

 

[Repro_Pro]

Careful examination of the film on a light table with a strong magnifying glass/microscope is the first step to narrow down and indicate where to start an elimination process.

 

[Slammer]

Depending on the Film type maybe an IR sensor issue perhaps?

 

[modgraph]

Recently had some film that was slit down and repackaged. Had all types of issues, edge fog, friction fog as well as an overall increase of base fog. Repackaged film did not appear any different cosmetically as it looked professionally packaged. Increased the imagesetter exposure and increased the processor speed (shorter development) and was able to produce acceptable films. Not the 1 mil lines that you are talking of but the difference was dramatic. Development temperature and times become much more critical when the time is shortened so this must be carefully monitored.

 

[ssutton503]

My first thought (after you wrote that you had looked into the development) was the focus on the laser or that perhaps the optics are dirty causing the laser to lose focus. You might try imaging the fine lines as a positive just to look at the lines. Maybe it would give you more information.

 

[Macmann]

Great ideas guys-thanks! First step will be trying a higher resolution-we can go 5080. My problem is I can't MAKE the issue happen-it just shows up. Thanks again for the input!

 

[Slammer]

Great ideas guys-thanks! First step will be trying a higher resolution-we can go 5080. My problem is I can't MAKE the issue happen-it just shows up. Thanks again for the input!

Ah, then in that case look at static discharge, especially if your dev is in a dry ambient.