USING A GRAY CARD

Using A Gray Card

Do not tip the card up to the light like the picture on the left. Too much light is seen by the meter

The middle picture is correct. Position the card parallel to the front surface of your lens like this.

Do not tip the card down like the picture on the right. Less light is seen by the meter.

Get the camera close enough so that only the gray card shows in the viewfinder. Once you have the meter reading, back off to frame the view as you like. Be aware that automatic cameras go back to their erroneous  ways as soon as the gray card is out of view. What is a gray card? Camera light meters see reflected light, but it is often useful to know the incident light (the light hitting your subject). With an 18 percent gray card you can get a reflected light reading which is essentially the same as reading incident light. Our gray cards are made from mat board. They have been painted to give results similar to an 18 percent reflectance Kodak gray card. This is equivalent to zone V. In the zone system, V is the middle tone half way between black and white. Why do we use a gray card? Here are several situations that benefit greatly by the use of a gray card to check the exposure. Whenever there is any sort of back lighting such as a bright sky or window behind the subject. When there is a light source such as bulb or light fixture in front of your camera. When there is any type of back light such as a bright sky or window behind the subject. When a large part of the scene has a fairly dark tone like a close up of a big black car. When a large part of the scene has a fairly light tone like a snow scene. These are lighting situations that fool the typical camera light meter. It never hurts to check the light reading with a gray card. If you get the same reading with the card as without, you didn't need it. If the gray card gives a different reading, you should generally use the gray card recommendation. Or, you could make several exposures to see which negative comes out best. Links to other web sites that explain the use of a gray card New York Institute of Photography Tips for Better Photographs Black Cat (maker of the Red-Eye Pens and other specialty products) The University of Colorado's School of Architecture and Planning Visual Resource Center Instructions on        photographing your projects tells why and how to use a gray card. B&H Photo place to purchase genuine Kodak 18 percent Gray Cards the Image web site explains the use of a gray card to get the correct color when photographing a gemstone How can you make your own gray cards?