View Full Version : Adjusting for White Balance Question


Ray Sigmond
March 3rd, 2005, 01:11 PM
Curious to know what most use to adjust for White Balance.

Do most of you use a white piece of paper or

white balance card
http://www.bhphotovideo.com/bnh/controller/home?O=WishList.jsp&A=details&Q=&sku=300868&is=REG

Warmcards
http://www.warmcards.com/

or GretaMacbeth products
http://usa.gretagmacbethstore.com/index.cfm/act/catalog.cfm/subcategory/ColorChecker%20Charts/category/Munsell%AE%20Color%20Books%20%26%20Charts/browse/null/MenuGroup/Menu%20USA.htm

Martin Costa
March 5th, 2005, 10:04 AM
I use a bit of card, although its frayed and smudgy round the edges. I'm such a pro!

Bill Hamell
March 6th, 2005, 09:25 AM
I use a piece of white foamcore or 8 1/2" x11" warm card that I print myself.

Mr. Bill

C. Byrne
March 10th, 2005, 03:02 PM
I just got some warmcards in the mail. I've seen them used on sets and really liked their results. I'm testing them out tomorrow.

Josh Hibbard
March 10th, 2005, 03:30 PM
Thos warmcards look intresting, But I dont want to buy six for sixty-five dollars.

I just want one light or medium grade 3x4

Does anyone see where thats an option, or does anyone have a set they dont use all of?

Ray Sigmond
March 10th, 2005, 09:34 PM
Here is Walter Graff's response to this same question in DVXUser

"Here is a sort of non technical look at white blance. White balance is a relatively simple process. Your camera uses the green color channel as a reference for every thing it does. So red and blue are always compared to green and you get the correct colors of the rainbow. So when you hit the black balance on a camera you'll see that the viewfinder shows black and suddenly the black seems to change levels. What you are seeing is the following. The camera looks at green and then compares the red to green and the blue to green if the red and blue do not rest on the same plane as green then the camera quickly makes them identical. That is what the different shifts of black are in the viewfinder when you hit white balance. Its first the green channel, then the red and blue channels being compared to green and adjusted. White balance is similar but it uses the white peaks of the colors and makes the appropriate adjustments. So the idea is that if you aim the camera at something white it will reflect the color temperature of the light hitting the white surface. The camera sees where green is in that reflection and makes red and blue the same. And when its done you get a camera that sees white the way you do. Actually (you have an auto white balance in your head that makes adjustments on the fly). So the secret to a good white balance is to fill up your frame with at least 80% of something white. It could be a white sneaker (tennis shoe), white piece of paper, a white shirt, etc. And that white need only reflect the color temperature of the room you are in. If its a mixed color temperature you have to decide which color temperature you want to predominantly be represented in a shot. So if your room is all 3000k and you have a little window in the background with 4600k outdoor light, but WB for just the 3000k, you get correct color for the room and the window looks blue. This is ok. It IS blue outside and you will not be able to find a perfect balance at such a color temperature extreme. You don't need to. But say you are in a room with 4000k ceiling florescent's and you are going to supplement your lights with 3000k lights. You could gel lights but why bother. Simply adjust your white card so it get s a bit of both color temperatures and you will get a balance of the two and a good white balance. Use a monitor to see the results. If it looks to blue WB again and get more flouro and less incandescent. Too orange, get more incandescent and less flouro. If you remember from my lecture ( I gave everyone a swatch book), you can use gels to help crate subtle WB effects. Warms cards are a waste of money and you can do the effect better like this. If you have a Lee dealer you know, ask for a cinematographers swatch book. If not check the website. I think you can order one free. This swatch book contains about 50 4"x4" gel samples including color temp blue (CTB) and color temp orange (CTO). WIth these you can do the exact same thing as an $80 warm card. So remember I said that white balance was the comparison of red minus green and blue minus green till they were all in the same place? But what if I took apiece of 1/8th CTO from that swatch book and placed it in front of the camera so that when I aimed my camera at something white, the white had an extra amount of that orange gel? If I white balance the camera will subtract more orange giving me more cyan and that would make my picture cooler looking. And the opposite is true. If I took an 1/8 CTB and did the same, I would add blue giving me more amber and the picture would look warmer. Using 1/4 of either CTB and CTO gives me appropriately more of each color. That is what a warm card is. So don't waste your money on one of these when you can do the same trick to more of a degree with a pice of gel. These premade plastic white cards and warm cards are fine if you want to use them but they get old, fade, get dirty, etc so eventually you might not have such a white card. And white is everywhere so once again its free."

http://www.dvxuser.com/V3/showthread.php?t=20201

Martin Costa
March 11th, 2005, 01:52 AM
Ray you are awesome. :-)

Samuel Birkan
March 11th, 2005, 08:02 AM
OK so how do I get my hands on one of these swatch books ?

Ray Sigmond
March 11th, 2005, 09:36 AM
<<<-- Originally posted by Samuel Birkan : OK so how do I get my hands on one of these swatch books ? -->>>

Here is a link for Lee Filters. These are the ones Walter gave us in the seminar.

http://www.leefiltersusa.com/NewLightProducts/LightNewProdSWB.html

C. Byrne
March 11th, 2005, 09:38 AM
Wow, thanks Ray!
That's a great idea. I just ordered a swatchbook from the Barbizon store in Chicago. And it's free!! This will give me so much more control w/ white balance. Too bad I won't have them for today's shoot!

Samuel, here is a link I found helpful for figuring out which swatchbook to get and who might sell them. http://shop.barbizon.com/docs/product/color.html

Jan van den Hemel
March 11th, 2005, 12:30 PM
This may be the stupidest question ever but...

What exactly is the purpose of white balance? I've never really used it before, perhaps I should...

Ray Sigmond
March 11th, 2005, 12:57 PM
<<<-- Originally posted by Jan van den Hemel : This may be the stupidest question ever but...

What exactly is the purpose of white balance? I've never really used it before, perhaps I should... -->>>

Jan read above where I copied Walter Graffs' comment and he explains it in detail. What camera are you shooting with Jan?

Samuel Birkan
March 11th, 2005, 01:00 PM
Thanks for the info guys, I called Barbizon in NY and they were out of stock so I called the Lee USA 800 number and ordered 1. Rosco at rosco.com also have an order form for swatches

Ray Sigmond
March 11th, 2005, 01:03 PM
Jan:

A good book for you to get a better unstanding of Lighting is called "Lighting" by John Jackman

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=332733&is=REG

Ray Sigmond
March 11th, 2005, 01:13 PM
ideally, you want the swatch that is 4" x 4"

Simon Wyndham
March 11th, 2005, 01:39 PM
White balancing is often over emphasised. One needs to remember that when you white balance you are taking away colour. For example if you were to film a sunset and white balanced on a card in the warm orangy glow of the sun, you will take away those very colours that you wanted to video in the first place.

White balancing is useful in mixed colour temp settings such as the one Walter mentioned or on sunny days with areas of shade visible (they will look a lot cooler than the rest of the picture). White balancing would also be useful for a situation where light is changing all the time such as shooting a scene all day long and wanting to keep the colours as constant as possible.

Often is is sometimes easier just to use either the tungsten or daylight preset.

The important thing is to remember that you aren't necceserily trying to make white look white in your shot. Your aim is to try and reproduce the colours as you see them as accurately as possible (special effects withstanding). Often if you look at white it isn't really white. If you know what colour temperatures are present in various situations, on the larger shoulder mount cameras you can set the kelvin number to your exact requirements and don't always have to rely on a whitecard balance so that colours can be reproduced more accurately.

Jan van den Hemel
March 11th, 2005, 04:41 PM
That's very interesting. I'm shooting with a Canon XM1 and during the last shoot I did, the light kept changing (alternating clouded and clear sky coming through the windows). The color correction afterwards was quite a task because every shot was different.

Simon Wyndham
March 11th, 2005, 05:58 PM
Yes, that can be a problem. The colour temperature will go higher (bluer) as the sun is clouded over.

This is why the idea of lighting sometimes needs to be clarified to non video people on a shoot. They wonder why things have to be setup because 'the light looks good as it is'. But they don't realise that on days such as when the sun is clouded over, then comes out again, that it can be a nightmare to keep looking constant in editing. Even worse when it is actually during a shot.

For a run and gun some use auto white. Auto functions do have their place, although as much as possible I would prefer not to. But in constantly changing light where it may change drastically during a shot, and there are no light control setups to speak of it may sometimes be the only solution.

Simon