Photographers often concentrate on the density and detail of highlights and shadows when they should actually be considering the most important or middle tones of the negative. Middle tones are the various tones of gray between the highlights and the shadows; that is, the densities that are not highlights or shadows are termed middle tones or intermediate tones. The middle tones vary with the type of film and the subject contrast. A negative should have a range of middle tone densities that correspond proportionally to the middle reflective brightness of the subject. A panchromatic negative that does not have proportionate midtones is contrasty or flat.

GRAININESS

Because photographic images made from film are made up of fine silver grains, the images may appear grainy or exhibit graininess (fig. 10-22).

All negatives show graininess to some extent. The most important factors affecting negative graininess are as follows:

The composition of the emulsion or the inherent graininess of the emulsion. That is to say, the size of the grains used to produce the emulsion.

The type of developer used. When fine grain is desired, a fine-grain developer with the appropriate film should be used.

The extent of development. Overdevelopment is a major cause of excessive graininess.

Exposure or negative density. Overexposure is another key contributor to graininess. As negative density increases, so does graininess.

Figure 10-22. Grain structures in emulsions.

Image sharpness. The sharper the film image, the greater the image detail and the less apparent the graininess.