There's no way of knowing (unless you have a REALLY good eye) that the piece of white paper/foamcore is pure white :-(
You can always colour correct in post if you have to.

Foamcore is cheap so I'll buy a 4' square piece of it and then cut it into more manageable sizes for white balance purposes.
BTW, this stuff makes an excellent reflector/bounce card for fill light. Just don't get it too close to the light or it will melt/burn.

I white balance under the lighting that I'll be shooting in.
That is, if it's an indoor office with all flourescent lights, place the white card directly under one of these and do it there.

If it's a mixture of indoor and outdoor lighting, try to balance to the predominant lighting (in this case, flourescent) and let the windows go blue.

I generally have a light kit with me so I'll leave my camera on the 3200 K preset and ignore any other lighting.

Mike

Whatever happened to the translucent white lenscaps that used to be a standard out-of-the-box accessory on the early camcorders? You just capped the lens, pointed it at the main light source, and set your white balance.

this is one of those questions that, until you try some different things, you won't know the advantages of manual vs. automatic.

Search at bhphoto.com for white balance cards, they have one for about $5 . I got 4 or 5 and put 1 in each camera case and have a few spares (already left one behind). They have a little drawstring on them and I pull it under my belt loop to keep it with me most of the time. Problem is it sticks out like a sore thumb when you wear dark pants at a wedding.

I almost never use auto WB; it's either a full manual with a white card or an appropriate preset on my camera, either indoor or outdoor. If I have time, I set the camera where its likely to be positioned, and put the white card under the light where the action is (like the alter for a wedding ceremony), fill the frame with the card, and manually WB. In a run and gun situation where the light changes from room to room or indoors / outdoors, I'll just change to the appropriate indoor or outdoor preset on the camera and adjust in post if needed.

Also, look into Warm Cards from Markertek.com. I love those things. They make such a HUGE difference!

www.dsclabs.com make a product called CamWarm.
Includes a CamWhite card and three blue CamWarm cards.

I just checked out those warm cards online. And while they do give you another option for white balance, wouldn't it make more sense to just create that same warmth with color correction under Vegas. It seems like if you started with a white card, then other colors either side of that could be done in Vegas. Of course, I guess you could use a warm card and then also use CC in Vegas to make everything appear as though you had originally balanced to a white card.

The benefit to not doing it in post though is that you do not have to encode each frame with the color correction, thus you save time.

j razz

Great question, and I'd sure appreciate if anyone could tell us/me how to do that, say with my Panasonic 3-ccd consumer camcorder... I've been using auto balance for my greenscreen shoots, but I end up looking too "orange" in the post video, and have to color correct in post, which is a hassle.

Anyone have a link to, or how-to, for what to do? I'm using a panasonic PV-GS120.

I know, I know, it's not a big impressive fx1 or whatever, but then again I don't have to impress any clients, these are all for basement greenscreen shoots.

I have SM's DVRrack, but didn't learn how to use it... (on my to-do list).. it does have wb cards.

Ken

The thing about using a grey card is that you always know what colour it is, it is your reference. Then, even if you make a mess of the manual white balance, provided it's in shot for a frame you can fix the error in post.

The problem with using Aunty Jane's dress or John's shirt, is whether they really are white, or cream, or white with a hint of blue, or... you get the idea. ;-)

Take a look at this: ExpoDisc

It is somewhat expensive but works very well. I use for both Photo and Video.

My method is a 12x18 artist canvas board cut and taped down the middle so it folds that doubles as my shoot record holder. Just lay on ground, zoom in AND ADJUST EXPOSURE (I noticed this has not been mentioned but is relevant) and wham!

Incidentally my SONY FX1's auto white balance is as good as manual in good light and a contrasty scene.

I use a $50 Lastolite white balance screen. It is 20" open and folds to about 8" so it's not to bulky. My multi camera shoots go much smoother in post because with three XH-A1 cams being set to the same 18% greyscale dependent upon the exact positioning of each camera they usually require minimum work to match each other in post. I use the larger size because you need to be able to fill the screen with the balance color. My 20x zoom with the 20" screen lets me reach out a little and keep the camera where it will actually be. The cards or pieces of paper (8-1/2"x11") will limit the ability to get a true reading as they will need to be much closer and/or not fill the screen as well. Also I usually tilt the WB screen 3-10 degrees to pick-up the light coming in. If you hold the item perpendicular or tilted down you will not be accurately reflecting the available light at the subject.

I also use the Lasolite foldable- it's white on one side and silver reflector on the reverse. I never do auto WB with my PD170- I hold the Lasolite in front of the lens so that it fills screen and let the camera run for at least 5 seconds. After capturing, you can really see the difference in light where it has adjusted the WB, on your timeline.

i use my self made 4 tiered blue cards.. and of course my 18% greay card.. :)

doesnt have to be perfect for what i do, but these work and best of all theyre free.. i samples colours from blue card brochures and expanded those..

the grey is actually calibrated..

so long as it looks good and eases up my multicam colour matching then im happy.. works for me..

pure white can sometimes throw off the camera.. canons tend to lean toward yellow, sonys to red and panas to cooler colours...