Zone System for Motion Picture Film

The Zone System is valuable for complete control in exposing motion picture negative. "The ZONE SYSTEM for 35 mm PHOTOGRAPHERS" by Carson Graves, Focal Press, $29.95. is applicable to motion picture negative. All other Zone System books I have found are more complicated than necessary for motion picture film or are out of print.

Order the book if you can't find it locally. When the book arrives study this section together with the book, "Definitions for Zone System" and "Graves Page-by Page". Here are some things that you can do before the book arrives. You will need two Gray Scales and at least one Gray Card. A Gray scale has gradated patches printed from white to black. Kodak currently sells a "Color Separation Guide and Gray Scale (large)" Q-14 Cat # 152 7662. Don't bother with the included instructions. Camera stores should have these. If others are available let me know. Keep them in covers to keep them clean.

A slide projector is very helpful to view transparencies. You might mount and project some negatives too. There are filmstrip projectors out there for not much money that will take both filmstrips and slides. They were used in schools and industry before video. These projectors are also very useful for table top lighting and as follow spots. (See Follow Spot Alternative)

Find a lab that sells and processes 35 mm motion picture film in still camera rolls. .

RGB Lab. 816 North Highland Ave. Hollywood CA 90038, 323-469-1959 They have 6 different Kodak stocks at standard ASAs. 3 rolls for $10. $8.50 for developing the negative, making 36 transparencies, return postage and a new roll of film. They also have Fuji stocks.

Seattle Film Works no longer does motion picture film. Let me know if you know of other labs so we can share the information.

Four reasons to start with still cameras and motion picture negative developed by a still lab: 1. Most motion picture labs will not develop short rolls. 2. The labs that do print motion picture still negative only print at "mid light" so you get back what you expose for with no adjustments. 3. You are working with real motion picture film. 4.It's cheap! Most labs will "push" the films for a higher ASA, but I recommend that you master regular processing and mid light printing first.

First a little review: Negatives exposed and developed by still photographers are printed on paper. Light areas in the scene become dark areas on the negative and dark areas on the negative restrict light when printed on photo paper leaving it light. The process is really a negative - negative process. Motion picture negative printed on motion picture print film becomes a transparency which is projected. For motion picture film we don't have the developing and printing freedom that black and white still photographers have. When reading books about the Zone system think about the print on film as a transparency. Ignore the sections about special developing and printing. (Graves shows the negative to print process quite well in his book.)

INCIDENT LIGHT is the light ON a scene. REFLECTED LIGHT is the light reflected BACK from the scene to your eyes or camera. Incident light is reflected from or absorbed by objects in the scene. The Zone System relies on reflected light only, but we will master measuring both incident and reflected light. Most Zone System teachers usually concentrate on exterior photography. We will apply the system everywhere.

An INCIDENT LIGHT METER measures light falling on or incident to a scene. This type of meter is utilized by placing the meter in the same place as the subject. The light sensing element, usually a white plastic hemisphere or flat disk, is pointed at the camera. When measuring light with an incident meter be certain that your body does not shadow any of the light that would otherwise be falling on the meter.

A REFLECTED LIGHT METER measures light reflected off a subject. This reading is typically done from the camera's position with the meter's sensing surface facing toward the subject.

A SPOT METER is a very useful type of Reflected Light Meter. Where the general reflected light meter measures and averages the light reflecting from the entire scene, the Spot Meter typically measures an area that fits within a 1 degree angle of view. That 1 degree area is defined by a small circle seen while looking through the meter's viewfinder. The meter measures only the reflected within that circle.

A THROUGH THE LENS (TTL) METER is a reflected meter built into the camera. It measures the light reflected off the scene the camera sees and travels "through the lens" and falls onto the meter's sensing elements inside the camera. Most cameras using these meters automatically adjust the camera's exposure.

Each ZONE is one f stop (or t stop) more (double) or less (half) brightness in the scene or exposure on the negative. The middle of the Zone Scale is Zone V, Neutral Gray (18%).

NEUTRAL GRAY (18%) has been established by film and camera manufacturers as the average reflectance of an average scene for rating film speed, measuring light from a scene and reproducing the same result as seen in the original scene. Don't worry about 18% not being in the middle of a scale of 100. (It is logarithm wise.) A reflected light measurement of a Gray Card is an incident light reading.

GRAY SCALE. The maximum range of ink differences on paper from black to white that can be printed is about 7 Zones or stops. Most films and even some newer professional video cameras set at one exposure will record a contrast range greater than a gray scale printed on paper. The scales on most gray scales are not Zones.

THRESHOLD is the point where a minimum amount of light falling on a negative just barely causes some density when the negative is developed. Any amount of light below threshold does not effect the negative. It will all be the same density of "black" on the print.

D MAX (Density Maximum) is the point where more light falling on a negative makes no more density on the developed negative. A bright part of a scene that has already caused the negative to reach D Max will look exactly the same "white" on the print as another part of the scene that is even brighter, (even if it is 2 or more times brighter.)

If we set exposure according to a reflected light reading from a gray card, or a white card, or a black card, in all cases the prints should all come out neutral gray. A reflected light meter's indication, if used without interpretation is designed to render the metered surface as a neutral mid-tone on the negative and subsequently the print. Because of this a black cat in a coal bin or a white cat in snow should will all come out neutral gray if you strictly follow a reflected light meter reading. The automatic exposure camera or reflected light meter does not know what it is looking at. You have interpret what the camera or reflected light meter tells you. If you take a reflected light meter reading of a neutral gray object or gray card in a scene the rest of the scene should be properly exposed IF it is an average scene. Sunsets, back lit signs, scenic backings and light sources are NOT average scenes and must be measured with a reflected light meter and you must decide where to place the exposure of each area in the scene on the negative. The sunset should be much brighter than the black cat but we usually want some detail in both.

The % REFLECTANCE scale is a measure of the amount of light reflected back from any object in a scene. A mirror could be 100%, black velvet close to 1% or 2%. Remember gray scales on paper will not reproduce this much contrast.

Some photographers base their exposure on neutral gray and measure other areas in the scene as f stops over or under (+2, -3, etc.) neutral gray. It is helpful to learn the table below.

Some common examples of the amount of light reflected from objects and faces are:

The ZONE Reflectance Comments Stops under/over.

Zone   Reflectance Comments
Stops Over/Under
Zone IX = Snow 95% No Detail
Zone VIII = Off White 80% Some Detail
Zone VII = Light Grays 70%  
Zone VI =Caucasian Skin 35%  
Zone V =Middle Gray 18% What light meters assume as average
Zone IV =Brown Skin 16%  
Zone III =Black Skin 13%  
Zone II =Very Black Skin 9% Some Detail
Zone I =Black Velvet 2% No Detail

Zone V = Middle Gray 18% What light meters assume as average 0

Zone IV = Brown skin 16% -1

Zone III = Black skin 13% -2

Zone II = Very Black skin 9% Some detail -3

Zone I = Black Velvet 2% No detail -4

Some films may record this range of Zones and others more or less. Your challenge is to find what the film you choose can do by testing.

These reflectance values do not change with different levels of incident light on a scene.

A still camera on automatic will expose an average scene just fine for average scenes, but this isn't good enough for real control. It is important to place skin tones and object brightness in the proper Zone so that everything in the scene comes out as you intend. In mixed lighting situations this can be a challenge, such as an interior shot with sun light also coming through the window.

Outside, with constant sunlight, we often find a 9 Zone / F-stop range within a scene. Inside with various lighting and especially a scene that is part inside and part outside, the brightness range can exceed 9 Zones and the ability of any film to record the whole scene brightness range. In the case of film we can let the whites "burn out" (the negative cannot get any darker), and let the blacks "stay black" below threshold (not enough light to cause any effect on negative). Remember we don't have the developing and printing control that black and white still photographers have.

Our eyes/brain are NOT very good judges of contrast because we can see a much greater contrast range (about 13 stops or Zones) than film or video. We are also more aware of color differences, but for exposure control we must first think in terms of brightness of objects in the scene and density on our negatives and prints.

We need a reflected light meter (a spot meter is best) to measure the brightness range of the scene and to determine the exposure. If we have a neutral gray reference such as a gray card in the scene we can read its exposure and set the lens for that calculated exposure setting. If we have a fully lit Caucasian face, it should measure 1 Zone/stop brighter (Zone VI) than our exposure setting. A dark face should be Zone V or darker. With a gray card in the scene you can learn to judge what objects are neutral gray.

Thanks to Bill Bennett for editing help on these sections.

© Copyright 1999-2004 Ron Dexter. All Rights Reserved.