Digital Camera saturation and brightness of the tones of the image

The tone, saturation and brightness of the tones of the image depend on the characteristics of the film , the exposure level and the color of the light (6.4). We can represent the operation of color film as three perfectly joined ladders, that behave as a single emulsion as long as a determined type of light is used. In this ladder, the color exists only in the exposure latitude ; this means that the colors can be destroyed , reduced to black or white by an underexposure or an overexposure. While in black and white the negative is the common origin of prints and transparencies, in color there is a much more drastic alternative. It is true that prints can be obtained from slides (this constitutes the immense majority of pictures we see published) and transparencies from negatives (movies), to us what is relevant is that the characteristics of reversible material (slides) and the negative are very different.

Sensitivity, Contrast and Grain
As in black and white, the sensitivity of film implies a determined characteristic contrast and it's corresponding exposure latitude, as a larger or smaller size of grain and sharpness. In each type if material:

A low sensitivity emulsion is characterized by maximum contrast low exposure latitude, maximum sharpness and minimal grain.
Medium sensitivity has a lower characteristic contrast, more latitude and acceptable levels of sharpness and grain.
High sensitivity material is characterized by minimal contrast, maximum latitude and size of grain and minimal sharpness.

If we consider film as an only emulsion then the meaning of characteristic contrast is the one we already know: when the brightness differences of the original scene diminish, it is a low contrast emulsion; if the differences are amplified, the emulsion's characteristic contrast is high. All reversible material has a high characteristic contrast, which will be greater, the lower the emulsion's sensitivity is; color negatives are of a normal or low characteristic contrast, as much lower as the emulsion's sensitivity is high. This, in practical terms, influences in the visual contrast of the final image and in the exposure latitude we have. Also, if we consider that color emulsions are made up of three independent sensitive layers, the emulsions characteristic contrast also determines the magnitude of the tonal differences of the colors. The contrast of every layer indicates its degree of response to differences in brightness of it's respective primary color . For example, if we photograph a scene made up of two zones of different primary colors, the characteristic contrast influences in the magnitude of tonal change when passing from one to the other; the greater the contrast, the greater the tonal difference. Low sensitivity emulsions are associated with a greater color saturation . The color's contrast is reduced when the sensitivity increases.