Equipment Catalog

Delta 1 CPM 22010 18% Gray Card

The Delta 1 CPM 22010 18% Gray Card is an accessory used to help determine the correct exposure for film and video. The card has been colored a special shade of gray, which is designed to provide an ideal standard for measuring mid-tones as the basis for exposure and color settings, as it is chromatically uniform and spectrally neutral.

The 18% Gray Card has two primary uses: for providing a standard subject for light-metering, and for white-balancing.

When used for light-metering purposes:
With a reflective light-meter, the reading given will be the same as that given from an incident light-meter. This is assuming that the card is positioned correctly, with respect to the light-source and the meter. The reading given by the light-meter will represent the correct exposure setting for the mid-tones only — the exposure of the shadows and highlights will depend on their difference in illuminance as compared to the mid-tone exposure given by the Gray Card.
With a camera or camcorder’s built-in meter, the device will deliver similar readings, when set to adjust exposure automatically. For manual exposure, the broadcast standard is approximately 50% IRE, for camcorders that display brightness information as a percentage. Consult the manufacturer’s operational manual for instruction on how to interpret the camcorder’s exposure readings.

When used for white-balancing purposes:
Once the desired exposure has been set, it is also possible to use the Gray Card for white-balancing. This may seem counter-intuitive, as calibrating the color-balance electronically is called “white-balancing” — however, white-balancing to the Gray Card will actually render a more accurate representation of color than using an improvised white surface. The shade of gray of the Gray Card is a special formulation of hue and saturation that is neutral in both chroma (color) and luma (brightness). The human eye is easily fooled into perceiving an off-white color as true white, and calibrating the camcorder to these false-white surfaces will cause the entire color spectrum to “shift” accordingly. It will render the off-white as true white, but all the other colors will be skewed relative to the referenced-white surface’s chrominance.
Using the Gray Card consistently for white-balancing throughout a shoot or production will ensure that all colors are accurately represented, as the camcorder will be referencing a spectrally-neutral standard. This can greatly expedite the color-correction process in post, as all of the colors displayed will be consistently “placed” relative to a constant and neutral chrominance standard.

A technique often used for still-photography, but useful to videography as well, is to take a shot of the Gray Card for each take or scene, to provide the editor with a reference subject for adjusting Hue, Saturation, Brightness, and Contrast in post-production.

Additional Resources:

Access, Instruction, and Support

The Delta 1 CPM 22010 18% Gray Card is provided for F&DM production students upon enrollment in one of the F&DM Department's production courses.

Access to the Delta 1 CPM 22010 18% Gray Card, like all of the department's A/V production equipment, is mediated through the Equipment Checkout Lab in accordance with course allocation assignments, and granted on an individual basis upon meeting specific criteria.

Any and all problems experienced with the Delta 1 CPM 22010 18% Gray Card should be reported to the Equipment Checkout Lab Specialist immediately; do not wait until returning the equipment to notify the Lab Specialist or Lab staff (See: Statement of Policies).