(b) Roller marks most likely occur in the first half of the developer rack,
where film is most sensitive to impressions. The marks can be on either side of the film.
(c) To determine which side of the film a particular mark is on, use
household bleach to remove the emulsion from one side. If the marks disappear, they
were on that side of the film. This will help you determine whether the marks are made
by the inner rack rollers (top of the film), the outer rack rollers, or both.
(6) Check the transport path. Check for worn or warped film guides and
loose fasteners. Ensure that the film moves through the racks individually. Plastic or
metal parts that are out of adjustment can cause film scratches in the direction of film
travel. Burrs, dirt, or dried chemicals on the feed tray, shoe assemblies, or crossovers
can also scratch the film repeatedly.
(a) If scratches are not predictable, sifting dirt in the solution tanks
could be the cause. They could also be caused by film, chemical, or film handling
Plus density marks occur before the fix. Minus density marks occur in the fix
(b) Film is most sensitive to impressions in the developer rack. As with
roller marks, it is in the developer rack that scratches most often occur. Scratches at
the top of the film may be caused by the crossovers or top guide shoes. Similarly,
scratches on the bottom may be caused by the guide shoes in the bottom of the rack
being out of alignment or dirty.
(c) To find the location of the problem, remove the fix/wash crossover.
Feed a sheet of film. Retrieve the film from the fix rack and inspect it for scratches.
Replace the crossover, making sure it fits correctly.
(d) You should consult the sensitized materials manufacturer for a
solution to any problems you cannot correct.
(e) Remove the dryer and repeat the process, adding each component
in the film path after the film has passed through the previous one. This procedure
should isolate the problem. If the problem is in a rack, refer to paragraph a(1), above.
(7) Check the tanks. Clean the tanks and check for algae build-up as well
as for evidence of leakage. The wash tank drains automatically when you turn the
power switch OFF. Leave the top cover slightly ajar to allow the tank to dry out. Failure
to do this causes dirt to accumulate in the tank and permits algae to grow. Dirt transfers
to the film as the film passes through the tank. If the incoming water contains significant
impurities it may cause streaks or spots on film. Filtering the incoming water supply
helps eliminate this problem.