18% grey card use for film

[Paulo]

Still new to the forum and handling an SLR. Seeking help.

I have a Nikon N80 and generally shoot Fujifilm Superia 400. I've read some old photography books to familiarize myself with aperture and shutter speed functions. Outdoors, I've had generally good experiences shooting and my images coming out the way I intended. However, I made my first attempt at indoor portraits using Fuji Pro 160C & Kodak Tri-X 400, SB-28 hotshoe flash and a couple of friends as volunteers. My light was consistant but nasty (j-rigged, single track light with a "natural light" rated flood bulb). Wasn't familiar with the importance of diffusers & backlighting then so none used. Anyway, most of my pictures came out either really dark or really burned out. Friend said it's probably because I wasn't metering consitently.
How could I use a 18% gray to correct this in the future? Bought one recently but not sure what I'm suppose to do with it: focus my camera on it? take a picture of it? take a picture with my friends holding it?
Can you assist? The film is almost $10 a roll and I just feel like I wasted it, as well as my friends time?

[johnastovall]

Here's how to use one.

LINK FIXED

[Sonny]

need to add an "h" to that link

[Bill]

First, know what area the camera is metering. The whole area, a spot? Learn it or the rest won't help.

Your camera assumes that what you are metering is an 18% gray card, a middle gray. If it is not, your metering will be off.

If you meter a white t-shirt, the camera thinks the light is super bright and cuts the exposure. Result=too dark.

If you meter a dark coat, the meter thinks the light is way low and increase the exposure. Result=too light.

You can learn what equivalents are to a gray card. Medium blue shirt, medium red. The red will look brighter because that is how we see red, as bright. But if you learn to see only the light/dark side, you will not need the gray card after a while.

You will also learn that if metering a white t-shirt or bridal gown directly, to open up the exposure 1-2 stops in compensation. If metering a navy coat directly, to reduce the exposure.

Once you know the story, you may want to adjust the exposure more/less for creative effects.

Place the gray card in front of your subject's face, pointing toward the camera, and meter on it. If your camera meters the whole scene, move closer until the card fill the viewfinder. It does not have to be in focus. If you move close, be sure you are not obstructing the light on the face/card.

[Paulo]

Thank you everyone for the link and information. I appreciate your time.

[Nevyn]

Also, if you're intending to keep going with this, buy yourself a light meter and learn how to use it - that way you won't need the gray card.

[Jeez, that was full of typos - corrected for my own sanity]

[Paulo]

Thanks Nevyn. The light meter with be my next item to add to my collection.