For some reason most
film technicians find sensitometry either boring or frightening. This is
unfortunate, for with only a basic knowledge of the photographic process, and
the ability to do your two times table, you can master all you need to know to
gain considerably more control over your picture making.
the word would suggest, is the technique we use for measuring and evaluating the
sensitivity of a film emulsion to light. The important part of the evaluation,
to cinematographers, is to know how much light arriving at the emulsion is
needed to produce the required density of image on the film after
between the amount of light, the exposure, and the darkening, the density, will
not be in the same ratio over the entire range of brightness recorded on the
film. This is important for in creating the mood of the final picture.
cinematographer should be very concerned to know how much detail will be seen in
the shadowed part of the image. Particularly if outdoors, they will wish look
for details that can be recorded in the highlights of the scene so as to know
how sky, sand, snow, etc. will be represented in the picture.
cinematographer Vilmos Zsigmond's opinion, lighting is the most important tool
for the cinematographer. "Lighting creates mood. The mood places the
audience into the story. You laugh. You cry. You feel happy. You feel sad. This
is done by us- cinematographers- mainly with lighting."
This is his time
of experimentation- a time that helps set his style of shooting, of pushing the
limits. It is all about how he relates to lighting. "In Hungary, the DP
lights and handles the camera," he says. "Not so, here. There, you
have everything- you are controlling the look of the images, the way the camera
moves- just one person, not two or three. The cinematographer is a very strong
colleague of the director, so much so that the cameraman/cinematographer, in
Europe, is 50% partner with the director. Sometimes, the DP will take over some
of the director's problems."
characteristic the cinematographer needs to be aware of is the relative contrast
of the film in use. Contrast and gamma are often confused. Gamma is a
measurement of the rate of change of the exposure/density relationship. Contrast
refers to the brightness range and the gradation between the highlights and the
shadows; it is therefore expressed as a ratio. The contrast range that can be
shown on a first-class cinema screen is the equivalent of seven stops of
developments in the construction of camera negative emulsions have made it
possible to manufacture a negative able to record the equivalent of ten stops of
brightness; this gives the film a contrast ratio of an incredible 1024:1.
Cinematographers must learn to recognize the difference between contrast (as it
is expressed as a ratio) and apparent contrast (as a 'soot and whitewash'