Pre-mission validation must be performed on the processing system before attempting to process mission material. These tasks must be performed so the system is operating within acceptable, established limits for that particular mission. Six tasks must be performed as follows:

The processing machine must be checked and verified to be operating correctly. This includes solution levels, transport system, temperature, replenishment rates, and water supply.

The measuring equipment, such as densitometers and pH meters, must be calibrated properly to ensure valid, reliable data.

The processing, printing, and support equipment must be checked and verified to be operating properly.

The composition of chemical solutions must be verified to be correct before processing mission material.

9 The sensitometric properties of photographic materials must be certified to be within established standards.

* A scratch test must be conducted to ensure all the rollers are operating properly and none of the guides are out of adjustment.

Once the pre-mission validation is complete, you are prepared to process the actual mission material. Before processing the film, you must attach a leader tab to the roll of film. The leading end of the film must be cut straight before splicing it to a leader tab. A piece of 7-mil Estar base film may be used as a leader tab. Processed X-ray film works well also. The leader tab should be about 12 inches long and cut to the same width as the film being processed (except when used to lead a control strip).

Mission processing includes the following procedures:

Protect the material being processed from dirt, dust, condensation, and other solutions, such as oil and water.

Avoid applying excessive force to the surface of the film; abnormal stress can cause pressure sensitization.

*Inspect the material being processed for physical defects before machine processing. Defects, such as tears, crimped film edges, and defective splices, can cause the film to jam in the processor.

* Ensure the film is processed in a processor that has been certified beforehand.

Monitor the processing temperatures and the transport and replenishment rates while the film is being processed.

Monitor the film exiting the dryer for correct dryness, possible defects, and image quality.

Follow the instructions concerning the storage of film (before and after exposure) carefully.

POST-MISSION IMAGE EVALUATION

After processing, the mission film is subjected to stringent post-mission evaluation for the following reasons:

* To determine whether or not the process met desired sensitometric goals and to provide feedback for process adjustment

To reveal improper procedures or techniques and to identify defective materials

To identify malfunctioning equipment

The post-mission evaluation should include three phases: image quality, image analysis, and laboratory evaluation.

Image Quality

The mission film must be inspected for defects, such as fogging, streaking, pinholes, and shadows. These defects are caused by foreign matter in the camera or on the aircraft window from which the photographs were taken.

You should also look for superficial defects, such as film tears, dirt, scratches, abrasions, or foreign marks. Defects found should be described and reported as to the actual frame position to help identity the cause, such as improper handling, processing, or other lab or maintenance procedures.

Image Analysis

Image analysis consists of density measurements made with a densitometer. The properties to be evaluated should include D-min, D-max, density range, and gross fog.

Laboratory Evaluation

Whenever possible, you should use samples of unexposed sensitized materials from the mission to produce sensitometric measurements and standards. This data should be used for comparison with the mission film after processing.

POST-MISSION MAINTENANCE EVALUATION

Photographer's Mates working in the Aerial Processing section must be able to supply accurate maintenance feedback information to the reconnaissance system maintenance crews. Since the end results are a true measure of system performance, this feedback will do the following:

Ensure that maintenance personnel become aware of possible system malfunctions.

Aid in evaluating overall system performance. The process of evaluating a photographic negative to determine system defects, as related to overall performance, is one of the most complete measures of system output. System defects noted during film evaluation should be recorded on a film maintenance feedback form and forwarded to maintenance personnel for action.

Frame Spacing

On all serial-frame camera imagery and panoramic camera imagery, you should include a space between each exposed film frame. While the space may differ in width requirements, it should be present. Frame spacing defects generally indicate that a system defect exists, such as a fault in the film-advance mechanism.

Image Overlap

Image overlap between successive frames provides stereo viewing capability and distortion-free imagery for a mosaic.

Instructions by the camera manufacturer contain tables with overlap specifications for serial-frame cameras and panoramic cameras. If the overlap is not met, the camera may be receiving an improper V/A (velocity/altitude aboveground level) signal from the system. In addition to improper overlap, this problem can cause blurred images.

Data Block

Each frame contains a data block and other pertinent information about the mission, such as film and flight direction, frame count, and so forth. In an infrared reconnaissance set (IRRS), the data block is usually recorded along the length of film periodically. Discrepancies in the image of the data block are usually caused by a malfunction within the sensor (camera or IRKS).

Static

When film loses or gains electrons (negatively charged particles), the film becomes either positively or negatively charged. This charged material seeks to return to a neutral state by transferring electrons from or to other objects. This transference can sometimes cause heat and light. When light occurs, it fogs unprocessed film emulsions and causes markings on the processed film. These markings may have a spider web or lightninglike appearance.

Shutter Banding

Banding is associated with focal-plane shutters. It is caused by defective shutter operation. Banding can be identified by the presence of uneven illumination streaks across the line of flight. This defect is caused by the focal-plane shutter slit, varying in size, and an erratic shutter curtain or erratic film transport through the focal plane during the exposure cycle.

Camera Light Leak

A camera light leak is often difficult to recognize. It can cause various nonimage-forming shapes and appear and disappear as the angle of light to the leak changes. The light leak causes areas of the film to become fogged.

Exposure

A negative that has detail in both the shadow and highlight areas is exposed properly. However, when evaluating the negative image, it is necessary to consider the subject matter because less exposure is required for light sandy beaches and snowcovered terrain and more exposure is required for dark terrain, such as forests and industrial sites.

When you are viewing a negative that has been exposed normally, patches of snow or light beach scenes appear overexposed. Inversely, patches of dark terrain or industrial sites appear underexposed. When the negative is completely underexposed or overexposed, the film sensitivity or filter factor (S/C) was set incorrectly or the automatic exposure control (ABC) in the camera system malfunctioned.

Vacuum

The lack of adequate vacuum in a serial-frame camera permits the film to sag away from the focal plane, causing the image to be blurred. The most common indication of insufficient vacuum is crooked data blocks.

Miscellaneous Defects

Reflections from the camera window of the aircraft, depending on the angle of the sun in relation to the window, can cause flare (nonimage-forming exposure) of the film.

Condensation on a camera lens can result in a halo effect surrounding film image points. This is generally caused by rapid aircraft descent immediately before a photo run.