9-8 Process ECP-2E Specifications
Filters
Filters are used to remove any insoluble material in the form
of solids and tars from processing solutions and wash waters.
If this material is not removed, it can adhere to the film being
processed, machine tank walls, rollers, lines, etc. Filters are
required in replenisher lines, recirculation systems, and
wash-water lines.
The ideal porosity rating for filters is 10 microns, but the
back pressure of a 10-micron filter is sometimes too great to
permit adequate flow unless oversize pumps or parallel
filters are used. Increasing the filter area will decrease the
back pressure, but also increase the cost of filters. Filters
with porosity ratings larger than 30 microns will produce
low-back pressure, but are of little value in removing
insoluble material. Another option is using high-porosity
filters in series. The high-porosity filters will slow the
clogging of the low-porosity filters.
Establish and follow a definite replacement schedule for
filters. Change filters every week or two, or whenever the
pressure differential across the filter housing exceeds 10 psig
(69 kPa).
Polypropylene, fiber glass, or bleached cotton are
acceptable filter media for all Process ECP-2E solutions.
Viscose rayon is not recommended for use with the
developer since it can cause adverse photographic effects.
Table 9-2 lists acceptable construction materials for filter
cores. Test all filters for adverse photographic effects before
use, as described in KODAK Publication No. K-12.
Crossover Squeegees
Processing solution loss and dilution are minimized by
crossover squeegees. They wipe solution off both sides of
the film strand using plastic blades, air streams, vacuum,
buffer plush, or other mechanical means, and direct it back
into the originating tank.
A crossover squeegee should be located on the exit strand
between stages of all countercurrent washes, and on all
Process ECP-2E solutions. Wiper-blade squeegees
*
(30- to
40-durometer hardness) can be employed, but must be
carefully maintained to make sure they do not scratch the
film. A general discussion on the use of squeegees is in “A
Review of the Effects of Squeegees in Continuous
Processing Machines,” Journal of the SMPTE, 79:121-123,
February 1970. Squeegee design details are given in
Module 2, Equipment and Procedures.
* A description of suitable wiper-blade squeegees is presented in “Spring-
Loaded Wiper-Blade Squeegees,” Journal of the SMPTE 81:742-796,
October 1972.
Dryer Cabinet
Carefully control drying of processed film. Insufficient
drying may lead to a physical defect called ferrotyping. If the
film is over-dried, the emulsion becomes brittle and the film
tends to curl or flute. Satisfactory drying leaves the film dry
without tackiness one half to two thirds of the way through
the drying cabinet. Allow the film to cool to room
temperature before windup. After cooling, the film should
have a moisture content in equilibrium with air at 50 percent
relative humidity.
Either an impingement or convection (nonimpingement)
dryer can be used. The impingement dryer dries film in a
shorter time and occupies less space than most
nonimpingement dryers. Regardless of the type, the drying
equipment must produce adequate and uniform drying to
prevent deformation of the film support or emulsion. Filter
the input air to the dryer to remove dust particles that can
stick to the film. A high-efficiency particulate air (HEPA)
filter, such as the Micretain Equi Flo filter (95 percent
efficient at 0.3-micron particle size) is recommended.
†
Film Lubrication
Edgewax 35 mm and wider films with a paraffin-based
lubricant (approximately 50 g/L). Full coat 16 and 8 mm
films with a less dense lubricant such as a 0.5 g/L PE
Tetrasterate solution (RP 48-1984). See Module 2,
Equipment and Procedures, for formulas and details.
† A product of Cambridge Filter Corporation, 7645 Henry Clay Blvd.,
Liverpool, NY 13088.