Definitions for The Zone System Applied
to Motion Picture Negative
I am ignoring the finer points of H and D curves, Gamma, shoulder, toe, etc.
so you can master the basics of exposure control before worrying about the finer
EXPOSURE: For a given film speed, the amount of light actually hitting the film
to make a mid tone gray, is exactly the same amount of light, regardless of
whether you are shooting outside in bright sunlight or inside a dim room. You
utilize your exposure time (shutter speed), aperture setting (f-stop), and filtration
to adjust the amount of light reaching the film it is the same in every case.
SHUTTER SPEED for motion picture cameras depends on shutter opening and camera
180/360 degrees x 24 FPS = 1/48 Sec.
SENSITIVITY: the films speed (ASA/ISO), it's ability to respond to exposure.
NEGATIVE / POSITIVE PROCESS. The negative / positive process allows many prints
to be made from one negative and provides some control over print density during
PRINT. A film print (slide/transparency/dailies/answer print) is a print on
film made from the developed camera negative.
REVERSAL FILMS (Kodachrome, Ektachrome, Fujichrome etc.) when developed are
transparencies of the original film. After processing, you get back the actual
film that was in the camera exactly as you exposed it.
SCENE CONTRAST RANGE. Every scene has a contrast range. Our job is to evaluate
the contrast range of every scene and decide where to place the exposure of
important objects in the scene on our negative.
BRIGHTNESS is the lightness or darkness of areas in our scene that our eyes
or camera sees.
DENSITY is the lightness or darkness of areas on a negative or print.
NEGATIVE CONTRAST RANGE is the range of exposure on the negative from where
light has not yet an effect on the negative to the extreme where more light
no longer has an effect. The minimum exposure that causes any density is called
"threshold" and the point of maximum density on the negative is called "D Max".
When the negative is developed and printed, ideally the print will reproduce
the same range of densities that the photographer exposed for. It is handy to
speak of contrast range in f-stops or Zones.
PRINT CONTRAST RANGE is the range of contrast in the final print.
Negative and print contrast ranges are constant for each negative or print stock.
Scene contrast range changes with lighting and object reflectance in every scene.
TIMING / TIMER. In motion picture work exposed and developed negatives are "timed"
by a timer. He views the negative of each scene and programs by computer the
amount of light and color balance that an automatic mechanical printer will
exposes the print film through the developed camera negative. The result is
a daily or answer print with a desired exposure/density and color balance.
MID LIGHT PRINT. A mid light (lite) print has no corrections by the timer and
the photographer gets back what he has exposed for. Timing can later correct/fine-tune
the photographerís printing lights during "timing the answer print".
Labs that develop still camera lengths of 35 motion picture negative make only
mid light prints.
PRINTING LIGHT. Printing lights are the numbers that correspond to the amount
of each 3 primary colors of light exposed on the print stock through the developed
camera negative. They usually range from 1 to 50. 1 is very little light and
50 the maximum. If a negative is dense (over exposed) it takes more light to
create a desired image density on the print. If a negative is "thin" (under
exposed) it takes less light to make image density on the print. Problems arise
with errors of under or over exposure.
"CALLING THE LIGHTS". Experienced camera-people after testing a certain batch
of negative will specify the printing lights for the timer for his negatives.
This is complete control. If there are slight errors in dailies, the cameraperson
knows how to make corrections in his exposures. The cameraperson has to be ready
to explain to directors and producers that the negative is all right and that
the answer print will be OK if there are exposure problems. Letting the timer
make corrections avoids some embarrassment in dailies.
LATTITUDE. I feel this is an often misunderstood term. It often means room for
exposure errors that the "timer" at the lab can correct. This is a sloppy approach.
If you have a low contrast scene you can "time" the negative at different printing
lights to give the desired print density. If the scene is high contrast (many
zones) there is little room for error.
INCIDENT LIGHT READINGS are fine for scenes of average objects and lit with
consistent light. Incident meters cannot measure light sources the camera sees,
sunsets, backlit scenes and signs, scenes through windows, and scenes that we
canít get to physically that have different light on them than at camera.
Note: No matter how you determine exposure, exposure on the film can be increased
OR decreased by filters, lens flare, dirty lenses, diffusion nets, special development,
flashing, etc. I would avoid all of these tricks until you can completely predict
your results without tricks.
REFLECTED LIGHT: Light reflected from a scene.
REFLECTANCE: The percentage of light reflected from an object expressed as %.
INCIDENT LIGHT METER measures light falling on a scene.
REFLECTED LIGHT METER measures light reflected off a scene.
SPOT METER reads small areas of reflected light, usually one degree.
EXPOSURE VALUE (EV): one measure of reflected light. Some light meters read
out in EV.
FOOT-CANDLES: one measure of incident light on a scene. Often used on stage.
(See Library/Glossary of Terms)
for more complete descriptions.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.