Digital negative (transparency)

The digital negative is a new technology which allows photographers to use digital files to create negatives on transparency film. These negatives can be used to contact print, or in some cases if the negative is made large enough (about 4x5") they can be enlarged. It is different from the Digital negative (DNG) file format, although this format may be used to create the digital images.

Before creating a digital negative it is important to know the process to which it will be applied. Since contemporary inks and printers cannot cover a gamut as wide as traditional silver negatives and it is imperative that each process have its own tonal curve to apply to a photograph so that the photographer can take full advantage of its gamut. Also, different processes react to colors in different ways; sometimes photographers print out a monochromatic negative in a specific color to get a specific contrast range. For example, some use purple inks and low contrast curves for the small gamut of cyanotype printing, while the platinum/palladium process necessitates a high contrast curve that works best with green ink. Before the color cast is added, however, it is important to remember to invert the image to ensure that the negative prints a positive if contact printing (some also flip their image horizontally since the final print will be a mirror image of the negative), or sometimes it may be left as a positive (in the case of a positive image on a dry or wet plate).

The photographer has a number of options to create a digital negative. Usually, the process involves a lot of testing and reprinting. Chemical procedures must be standardized to allow for repeatable results. First, a tonal scale is printed out on the transparency film and this is used to create a print using whatever process is being tested. Next, the print is scanned and the resulting tones are examined either by the photographer or by a program and a new contrast curve is generated to compensate for whatever inadequacies that may exist in the first negative. The photographer may also decide here to use a different ink color. The new negative is printed and again is tested. This process may continue for as long as the photographer deems necessary. The final negative should create a final print that has both blacks and whites, and a smooth tonal range between.

Digital negatives can be enlarged and printed using the standard analog gelatin silver process. However, since printers cannot spray small enough drops of ink to ensure detail in the smaller traditional sizes such as 35 mm, a larger format such as 4x5" is normally used.

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