Underexposure and Overexposure Film
Overexposure of black-and-white or color
print film leads to black-and white negatives that are more contrasty
and color negatives more color-saturated than normally exposed films.
Some manufacturers purposely underrate their print films 1/2 f-stop
slower than they really are. This works well for point-and-shoot camera
users whose meters are not so accurate. Visually, prints made from
overexposed color print negatives seem more color-saturated and
snappier. The contrastier prints appear sharper.
Straight underexposure of print film is
not a recommended procedure unless shadow detail is absolutely
essential and highlights can be sacrificed. In any event, limit
underexposure of color print film to no more than 1 f-stop.
Underexposure of black-and-white print film without attendant
processing adjustments will increase film speed, but at a price. Both
contrast and grain grow in proportion to the degree of underexposure.
If the subject is flatly lit, showing little contrast, and contains
lots of detailed mid tones, uncompensated underexposure can generate
"snap" in the image through increased contrast, while at the same time
maintaining reasonable grain. Underexposing color print film by one or
two f-stops still leads to acceptable prints because of the wide
exposure latitude of the material.
Beyond two f-stops, underexposure color
begins to wash out perceptibly.
Deliberate, uncompensated underexposure
is most effective with color slide films. Used judiciously,
underexposure increases effective ISO, color intensity, and contrast.
Underexposures of 1/2 to 1 full f-stop can be tolerated by most slow-
and medium-speed slide films. Underexposing higher contrast slide film
like Fujichrome 50, Velvia, or Ektachrome 50 HC does indeed yield
dramatic increases in color, but it does lead to decreased shadow
detail to a point where important information may be totally lost.
However, if you seek graphic, intense
color, just underexpose an ultra high contrast slide film like Polaroid
Presentation Chrome Color should be as intense as it can be and
contrast should compress considerably, adding to the drama.