Custom White Balance

[jalafata]

Now that I've converted to digital, I find myself worried much more about the White Balance setting, and feel I can't depend solely on AWB setting on my D10. Whereas AWB seems okay outside, I need "flash" for indoors with primary light source from flash. Otherwise the colors are wrong. And I'm uncertain on overcast days, or in bright shade. Therefore I'm interested in "custom WB."
1. Is this just set up once, or several times with differing lighting situations?
2. Do I use a grey card, or will 97% reflectance photo paper work?
Any advice please? Thanks!

[msvadi]

You are supposed to set WB every time lighting changes, ie if the light source or even shooting angle change. In my opinion a gray card works better than white. However, for the best results I think it's better to shoot RAW and adjust WB during conversion/postprocessing.

Some people achieve excellent results with the expo/disc http://www.expodisc.com/ . It's useful not only to set WB but also to determine exposure.

[hmhm]

1. Is this just set up once, or several times with differing lighting situations?
2. Do I use a grey card, or will 97% reflectance photo paper work?
Any advice please? Thanks!

When you make a CWB reference shot you "measure" the color of the ambient light by capturing a frame of a subject with neutral reflective properties (i.e. something white or grey) that's lit by that ambient light. That measurement of the color of the ambient light is, of course, only relevant to shots taken in that ambient light. For instance, the WB "stuff" inside the camera sees a CWB reference frame with a yellow tint, figures that this is a yellowish light (e.g. tungsten), and then subtracts out that amount of yellow from shots that use this reference.

Get a grey card, they're cheap. If you don't have a grey card handy, try using a sheet of white paper, but do note that different types of white paper do have slightly different tints. Some people use the same photo paper they plan to use to print on in their inkjet. It's the "whiteness" of the paper, i.e. the neutrality of it, that's important, not how reflective it is. Grey paper is just white paper with lower reflectivity. As far as CWB is concerned, a grey card looks like a white card in dimmer lighting, assuming they're both equally neutral.
-harry

[jalafata]

Thanks! Msvadi and Hmhm have been very helpful. One never stops learning with the hobby!

[evilenglishman]

At the top of every page on this forum is a link called Search.
This topic was discussed just last week here:
http://photography-on-the.net/forum/showthread.php?t=28648

:wink:

[5 Type]

Do I need to redo the CWB everytime I change my CF card (I guess so).

[slin100]

CWB does not need to be redone when changing CF cards. Once the camera has sampled the test image, the settings are retained.

[forrest64]

[quote="msvadi"] In my opinion a gray card works better than white.

You use a white card to set white balance and a grey card to set exposure.

[kahfluie]

ok so dopey question... is the idea to hold the card/paper/pringles up against the lens, or it at perhaps an arms length's distance?

[evilenglishman]

basically, put the paper in the area that you are going to be shooting and make sure it fills the frame when you take a photo of it.

put your image size on the smallest setting when you do this too as it will save space on your card

[PhotosGuy]

I just use white paper. Someone suggested elsewhere in the forum (Tips, I think) that it's a good idea to take the first pic of something with your name & contact info on it in case some honest person finds the lost CF card, so I've started writing it on the paper for the WB shot which is usually the 1st one I shoot. (BLACK magic marker!)

More info here:
Calibrating white balance using a white card..
http://photography-on-the.net/forum/viewtopic.php?p=179487#179487