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There are certain negatives that by their very nature are difficult to print. A photograph taken at night can often have a very long exposure range. Add reciprocity failure and you can sometimes find that making a good print is nearly impossible. If there are light sources in the photograph, ordinary dodging and burning are demanding at best, impossible at worst. The usual course of action is to reduce the print contrast by lowering the paper grade (or using a lower filter grade).

There’s a better way for those futile cases. Preexposing the print, or flashing (it’s also

Figure 76. In this print, the sky was burned-in. Feathering the burning between the left and right sides was critical. The results were more effective, but the print still needed additional work.

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sometimes called preflashing), can be effective; however, it can be difficult to walk the fine line that flashing requires.

Flashing is sometimes used with film to increase the effective film speed. Using flash-ing with film requires an extraordinary effort. It’s a little easier when used in the darkroom to augment your normal printing procedures.

As you might be aware, very low levels of light will not expose paper. When there’s enough light to produce minimum print density, it’s called the exposure threshold. When the light is nonimage light, the result is fogged paper. Exposing the print to light just below the exposure threshold gets it close enough that any additional exposure moves it over the threshold and there’s density on the print. Flashing the paper allows dense highlights on the negative to produce tonality in the final print without adversely affecting the shadows.

An extremely low exposure to nonimage light can reduce the contrast of a print. It can do so in a way more effective than simply reducing the grade of the paper. In a sense, it’s a free lunch. You’re not driving all the other tones closer together as you would by lower-ing the grade of the paper. Because most of the tones have virtually no change except the brightest highlights, the apparent contrast is effectively lowered. The relationships of the other tones, such as the midtones to the shadows, don’t change. It’s as if the greatest high-light densities on the negative were reduced shigh-lightly. A very neat trick when done with the right negative.

Figure 77. After making a print similar to figure 76, I used a dilute potassium ferricyanide bleach to carefully lighten the clouds. The results are effective, especially when compared with the original test print.

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There are many techniques for flashing the paper, such as using a low-wattage light-bulb or creating a diffusion screen. With practice these might work, but I use a way that is more effective for me. The advantage is its accuracy, consistency, and repeatability. To me, a technique is not very good if I can’t repeat it.

I use the enlarger to flash the paper. After setting up the negative in the enlarger, I remove the carrier and change the aperture. To make life easier, I try to do the flashing at the same enlarger height as that used to expose the print I’m making.

Finding the right combination requires a little persistent testing. Depending on the size paper I’m using, and the format of the film, I will start testing at one-second intervals at the smallest aperture. As in a maximum black or interval test, I make a series of expo-sures at that setting. Instead of black, I’m looking for the first interval that I see a tone slightly darker than the white of the paper. This is the exposure that is just beyond the exposure threshold. My exposure for flashing the paper is right below that. For example, if f/45 at 5 seconds is the first place I see tonality, I’ll try flashing the paper at f/45 at 4 seconds. If you can’t get below the exposure threshold with your lens’s minimum aper-ture, try using a #2 contrast filter or even a neutral density filter. After flashing the paper, I put the negative carrier back in the enlarger. With the image area of the paper covered with thick cardboard, I line up the negative and the easel. Resetting the aperture and timer to my previously determined maximum black settings, I make an exposure using any dodging and burning I feel necessary. For example, sometimes I’ll dodge the shadows a small amount to compensate for the additional exposure of the flash. This often isn’t nec-essary, though.

I’ve found a formula that seems to work consistently for my setup. Based on my max-imum black exposure, I close down two stops and make a preexposure at 10 percent of the time. With a maximum black time of f/8 at 8 seconds, for example, I would try flash-ing the paper at f/16 for 0.8 seconds. If you don’t have an electronic timer for your enlarger, don’t even attempt such a short exposure. Depending on the results, I might have to adjust the preexposure, though usually not by much. Although I don’t use a preexposure very often, this procedure has worked well for the several different types of photos on which I’ve used it.

The print is processed normally. Comparison is made to a nonflashed image, usually a test print, to see what the differences are and if further improvements can be made.

Some film developing tests with Kodak T-Max 100 and Ilford Ilfotec HC developer yielded very high-contrast negatives. In this example, an 8 × 10 print made from a 35mm negative had a maximum black exposure of f/8 at 8 seconds (fig. 78). Although the shad-ows have good detail, the highlights have almost no detail. I determined the preexposure to be f/16 at 1 second. The digital timer I use made the flashing at this exposure precise.

There is no dodging and burning in this photo (fig. 79), so you can clearly see the differ-ence this short preexposure made. However, burning is much more effective when the paper is flashed before the basic exposure. The effects are apparent in the print—there’s almost no difference in the shadows, but there’s substantially more detail in the highlights.

Although the print contrast looks the same (that is, the tones still have good separation), the tonal range of the print was decreased.

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Figure 78. At the maxi-mum black exposure, this test print was extremely high in contrast. Although the shadows have good detail, the highlights have almost none.

The print exposure was f/8 at 8 seconds.

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Figure 79. Using a pre-exposure of f/16 at 1 second, this photo shows considerable detail in the high-lights, without the blending of tones that might result from using a lower con-trast grade. There is no dodging and burn-ing in this photo, to emphasize the differ-ence that flashing makes.

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Flashing can produce effects that would otherwise be impossible to achieve in the dark-room. Although most prints don’t need this kind of excessive treatment, when it’s needed, flashing can be a godsend.