But HOW you actually follow their suggestions will determine if it works or not.

Like they said, the problem is that the white wall reflects more light than most other objects, so the camera's meter will try to make the wall look grey.

Using a hand-held light meter will only make a difference if you use an "incident" light meter. This would be held at the wall and aimed back at the camera to measure the light falling on the wall. Aiming a "reflected" light meter at the wall will give the same reading as the meter in your camera.

If you are shooting in Aperture Priority mode (Av on Canons), opening up a stop or two won't help because the camera will just increase the shutter speed to match. In this mode, you would need to adjust your Exposure Compensation to +1 or +2. Then, whatever aperture you choose, the camera will pick a shutter speed to give you a 1-stop or 2-stop overexposure for a white wall.

Exposure compensation will also fix the shot if you are shooting in Program mode.

If you are shooting in Manual, you need to adjust your shutter speed or aperture until the meter reads a +1 or +2 overexposure.

If you are shooting in full Auto mode, your white wall is probably going to stay grey.

Laura - I've never tried setting custom WB off of a gray card. I don't think that would help the exposure problem. Setting the custom WB off of the white wall would correct for any color in your light source.

Chris

You control the end-result tonal range (contrast) by lighting ratio. Basic lighting is with two lights. A main and a fill. Background control requires three lights. First concentrate on placing the Main and the fill. You always fill shadows from the camera’s prospective so the fill is placed on a line as close to the lens as is permissible. The main is placed higher and usually off to the side. Exposure is based only on the fill (expose for the shadows). Turn everything off but the fill and take your meter reading Best is incident reading. Second best is reflected reading from gray card. Third is reflected reading off face adjusted less one f stop (flesh is generally reflects one f stop more light than a gray card). Set main one f stop brighter than fill, ratio will be 3:1 result is normal contract image. Set main two f stops brighter than fill, ratio is now 5:1 higher contrast. Next set main three f stops brighter than fill, ratio is 9:1 for theoretical lighting. That all there is, film has a limited contrast range.

Setting ratio: If main and fill are equal in brightness, ratio will be 2:1, too flat. Start by measuring main to subject distance, multiply by 1.4, place fill further back to this adjusted distance. This causes the fill to be less intense by 1 f stop. Ratio will be 3:1, good money-making technique. One more time, back up by the 1.4 factor, ratio becomes 5:1 more contract more dramatic. One more time is 9:1 lots of contract very theatrical. Distance changes for brightness adjustments become less accurate for broad sources like umbrella lights. Stated another way, best to measure each lamps effect at the subject with an independent meter reading.

The shade of gray the background will obtain is controlled by the intensity of the background light. This third light is placed behind subject and shines backwards to illumining background. For white, adjust intensity via distance from background or by brightness setting. Same 1.4 factors apply. As a general rule white is achieved when background is illuminated about 5 f stops brighter than the fill.

Keep in mind, camera exposure is always based on the fill. The rule is “exposed for the shadows”. Adding two more lights, hair and rim (kicker) complements a studio setup.