Occasionally, the only record of an event is the original document that through age or use is no longer in its original condition. By use of appropriate corrective measures, certain defects in originals can be eliminated or minimized in the reproduction.

WRINKLED OR CREASED ORIGINALS. Reflection originals that are wrinkled or creased can be flattened by placing the original on a mounting board and then in a heated dry-mounting press. Mounting in this manner is permanent and should be considered carefully before being used.

Another method you can use to flatten an old photograph is to wet the photograph with water and squeegee it onto a sheet of glass with the emulsion toward the glass. The photograph must be removed from the glass before it dries; otherwise, it may stick to the glass.

STAINED BLACK-AND-WHITE ORIGINALS. Usually, transparent stains on black-and-white originals can be eliminated in the reproduction by using panchromatic film and a filter that is the same color as the stain. Details on eliminating images of stains with filters is discussed in chapter 3.

FADED BLACK-AND-WHITE PHOTO-GRAPHS AND MANUSCRIPTS. Normally, black-and-white photographs and other types of original documents that have faded and are yellowed should be copied with a film, such as Kodak Commercial film. An original with a weak, faded image should be copied with a film, such as Kodak Contrast Process Ortho.

SPECIAL APPLICATIONS IN COPYING

Special applications are used in copying to detect information that cannot be seen with our eyes under normal lighting conditions. Because these are special applications, they are not performed in most Navy imaging facilities, but are still worth mentioning. These methods involve the use of infrared and ultraviolet radiation and special types of films.

Black-and-White Infrared

Copying with black-and-white infrared films and infrared radiation can help in deciphering old, charred, or altered documents. This is possible because similar appearing materials can reflect and transmit invisible infrared radiation in different amounts. For example, two ink signatures may appear identical to the eye. However, when photographed with an infrared film, the two signatures may appear totally different.

A suitable infrared filter must be used when black-and-white infrared films are exposed. This is because infrared film is sensitive to visible light as well as infrared radiation. The infrared filter absorbs the visible light so the film image is produced entirely with infrared radiation. For specific filter recommendations, consult the data supplied with the film or the Photo-Lab Index.

Infrared wavelengths are longer than visible light wavelengths and do not focus on the same plane as visible light. Therefore, a slight increase in lens-to-film distance is necessary. A separate focusing scale for infrared is indicated on the focusing scale of most lenses.

Ultraviolet Radiation

Copying with ultraviolet (UV) radiation can aid in detecting chemically erased or badly faded writing and restoration or alteration of artwork because different materials reflect or fluoresce different amounts of ultraviolet radiation.

Photographing with reflected ultraviolet radiation in total darkness is possible because some of the ultraviolet absorbed by a material may be overlooked as visible light or fluorescence. Such photography in darkness is possible only when a material is illuminated with an ultraviolet source, such as the General Electric Uviarc. The fluorescence from a material illuminated with ultraviolet radiation should be photographed with a No. 2A (pale yellow) filter to absorb the stronger UV reflections. A recommended film to use for ultraviolet photography is Kodak Contrast Process Ortho film. Exposure tests should be conducted to determine the best exposure for an ultraviolet copy setup.

Do not use commercial ultraviolet lamps in which the lamp itself is an ultraviolet filter. These lamps transmit visible light that does not permit photographing a fluorescing original.