A contact print is produced when you expose a sheet of photographic printing paper through a negative with the paper emulsion and the emulsion side of the negative in contact with each other. Light is directed through the negative which controls the amount of light transmitted to the paper. The dense areas of the negative pass less

light than do the more clear or less dense areas. The image densities formed (after development) in the emulsion of the paper make a positive print that represents the tonal values of the original subject. Since the paper is in direct contact with the negative, the print produced is exactly the same image size as the negative.

When you are making a print from a negative by this method, only a 1:1 ratio is obtainable, but contact printing is generally a more rapid means of making prints than enlarging.

The quality of contact prints usually surpasses that of enlargements because there is no scattering of the image-forming light; however, with the ever-increasing use of small film format sizes and since only same-size prints can be made by contacting, enlarging has, for the most part, replaced contact printing in the Navy except for making proof prints.

CONTACT PRINTERS

Contact printing is the quickest, simplest, and most economical method of producing photographic prints. For making proof prints and small volume printing, all a contact printer needs is a sheet of glass, a light

Figure 11-2. Contact printing arrangement.

source, and some sort of padding. For large volume and fine printing control, a specially designed and constructed contact printer is used

Glass and Pad

For you to make contact proof sheets and an occasional contact print job, only a glass and a supporting pad are necessary. Contact printers, consisting of a sheet of glass hinged to a metal frame and a pad assembly, are generally known as proof printers (fig. 11-1). When such a device is not available or is not large enough for the negatives to be contact printed, a piece of 1/4-inch plate glass and soft padding (such as a rubber typewriter pad) can be used. Quarter-inch plate glass is heavy enough to keep the negatives and paper flat and in contact during exposure. The glass must be free of flaws, scratches, bubbles, and dirt. For color contact printing, the glass should be water white or crystal grade; otherwise, filtration is required to overcome the color tint of the glass. The edges of the glass should be beveled and the corners slightly rounded or taped. This is a safety measure to prevent cuts when the glass is being handled.

The pad should be at least as large as the glass. The pad provides a cushioned surface to press the paper and negative together under pressure from the glass.

To use either the proof printer or the glass and pad to make contact prints, you should place the printing paper emulsion side up on the pad material. The negatives are then placed emulsion side down on the paper and the glass is positioned on top. Then turn on

Figure 11-3. Using an enlarger as a light source for contact printing.

the exposing light (fig. 11-2). This, of course, is done in the darkroom under suitable safelight illumination.

Adequate pressure must be kept on the negative and print paper so their entire surfaces are in contact during the exposure. Any separation between the negative and the paper results in an unsharp point in the image.

The light source may be any controlled lamp for printing with a proof printer or glass and pad. An overhanging light bulb or a safelight, with the filter removed, connected to a timer is a convenient arrangement. In most Navy imaging facility print rooms, an enlarger is used as the light source (fig. 11-3).

Contact Printer

For large volume contact printing, a contact printer is more convenient. A contact printer is basically a box with exposing lights, safelights, and viewing lights inside with a glass top. It has a hinged pressure cover to hold the negative and paper in contact during exposure. Switches on the printer control the lights in the printer or the printer may have a built-in timer. Also, the contact printer may be connected to an external timer.

Contact printers are all built around the same basic idea. However, consult the manufacturer's instructions that accompany the contact printer for specific operating instructions.

A useful feature on contact printers is an adjustable masking device. This device is attached to the printer so it fits snugly over the printing glass. The mask consists of thin metal leaves used to frame the negative. These blades make it possible for the prints to have white borders or margins. To produce prints with white borders when using printers that are not equipped with a masking device, you can use hand-cut masks from thin, black paper.

The basic steps necessary for you to produce a print when using a contact printer are as follows:

Place the negative emulsion side up on the printing glass.

Place the paper emulsion side down over the negative.

Bring the platen or pressure cover down into the printing position.

Turn the printing light(s) on for the required exposure time.

Release the platen, and process the paper.

When you are viewing the negative under a white light, it has a shiny side and a dull side. The shiny side is the film base; the dull side is the emulsion side. A similar examination of photographic paper under a safelight shows that the paper has a shiny side and a dull side. In this case, the shiny side is the emulsion side; the dull side is the paper support. Photographic paper normally has a slight curl toward the emulsion side, although this is not true in all cases.

To make contact prints, you must place the dull side of the negative in contact with the shiny side of the paper; that is, they must be emulsion to emulsion. If the negative base is in contact with the paper emulsion, the photograph will be reversed. In some cases, such a reversal in the print is not easily seen, but it becomes strikingly clear when there are letters or numbers in the picture.