Drying Specifications, Turbulation Specifications

Chemical Supplies and Substitutions

Ferric nitrate is supplied in crystalline form as nonahydrate or dissolved in water as a 35 or 45% solution. Various bromides, carbonates, and hydroxides may be used interchangeably provided attention is given to effluent requirements and various molecular weights and activities are compensated. The following multipliers may be used to calculate between formulations:

•One gram of ferric nitrate nonahydrate = 1.31 mL of 35% = 0.93 mL of 45% solution

•One gram of ammonium bromide = 1.21 grams KBr = 1.05 grams NaBr

•One mL of 50% NaOH = 1.64 mL 45% KOH

If the odor or handling of acetic acid is a problem or undesirable, solid chemicals may be substituted. They are added as follows:

One mL of glacial acetic acid is equivalent to 1.05 grams of glacial acetic acid. One milliliter of glacial acetic acid can then be replaced by 1.35 grams of ammonium acetate. In potassium formulations, one mL of glacial acetic acid can be replaced with 1.71 grams of potassium acetate. The ammonium formulation is compensated by removing 2.2 mL of 28% ammonium hydroxide per mL of acetic acid from the formulation. The potassium formulation gets compensated by 1.49 mL of 45% potassium hydroxide for each mL of glacial acetic acid removed. This calculation is illustrated in the following example:

Formula calls for 10 mL of glacial acetic acid and

30 mL of 28% ammonium hydroxide. Substituting for 10 mL of acetic: 10 mL x 1.35 grams ammonium acetate per gram acetic = 13.5 grams ammonium acetate. The amount of ammonium hydroxide to subtract is: 2.2 mL ammonium hydroxide per mL of acetic or 2.2 x 10 = 22 mL. The formula becomes zero acetic acid, 13.5 grams of ammonium acetate and 8 mL of ammonium hydroxide

Drying Specifications

Drying photographic film depends on time in the dryer, the geometry of the dryer, the pattern of air flow and/or impingement on the film, the volume of air flow, the humidity and temperature of the air in the drying cabinet, and the efficiency of the final squeegee before the dryer. The optimum conditions for drying film must be determined for each processor, making allowance for film moisture content and static buildup.

Adequate drying of color print film can be achieved in 3 to 5 minutes using an impingement dryer with the following specifications:

Hole diameter	6.4 mm (0.25 in)
Spacing between holes	57 mm (2.25 in.)
Film-to-plenum distance	21 mm (0.81 in.)

Specifications for the dryer input air are in Tables 9-3,9-4,and 9-5.A nonimpingement dryer can be used if the drying time is increased to 5 to 7 minutes and the air going into the dryer is maintained at the specifications in Tables 9-3,9-4,or 9-5.

Upon cooling to room temperature after leaving the dryer, the film should have a moisture content at equilibrium with air at 50 percent relative humidity.

Turbulation Specifications

Turbulators are essential in the recirculation system for Process ECP-2E developer to provide uniform film processing. The turbulators are submerged in the solution and are located in such a way that the recirculated solution impinges uniformly over the full width of the film strand.

The requirements for solution turbulation are dependent on film transport speed. Machines with lower speeds will require more turbulation than faster machines. Good process uniformity can be achieved at a film speed of 165 ft/min (50 m/min) using the design guidelines in Module 2, Equipment and Procedures, Table 2-2, Developer Turbulation Design Guidelines, Process ECN-2,ECP-2E,D-96 and D-97. Precise turbulation design must be determined specifically for a particular processing machine to provide for good uniformity of development. The guidelines in Module 2 give helpful starting points for such designs. Backup rollers opposite the turbulators may be necessary depending on strand tension, strand length, film format, and nozzle pressure.

9-14	Process ECP-2E Specifications