Custom white balancing

Sharkbait · Sep 21, 2005

Possibly dumb question...

Should I use a pure-white card or an 18% grey card to do a custom white balance (on a 20d)?

Digital Matt · Sep 21, 2005

White (that's why they call it white balance

)

ksmattfish · Sep 22, 2005

The 20D manual says you can use a white card, although in one of the little note blurbs under that section it says an 18% gray card gives better accuracy.

Meysha · Sep 22, 2005

It always made 'sense' to me to use a white card because it is 'white' balance but everything I've read says to use an 18% grey card. Coz it's the middle of the tonal range or something like that.

Digital Matt · Sep 22, 2005

I always fill the frame with something white, and get great results.

ksmattfish · Sep 22, 2005

I think the key is to have a color neutral surface.

Sharkbait · Sep 22, 2005

ksmattfish said:
The 20D manual says you can use a white card, although in one of the little note blurbs under that section it says an 18% gray card gives better accuracy.

See that's what threw me off...it seems to me there's a big difference between pure white and 18% grey. :? So I wasn't sure which to use. I actually tried both, and the white seemed to give a more bluish hue that I'd have to correct with a warming filter action in PS, whereas the grey card gave a result pretty close to the AWB, which to me usually looks a bit too warm (white wedding dresses coming out with that warm yellow/orange cast.

I'm getting less and less impressed with my 20d by the day. :meh:

lazarus219 · Sep 22, 2005

the camera see's everything as 18% gray, so if you give it an 18% grey card to work with, it should be perfect, but more often than not it won't get it 100%, on a 20D you should be able to fine tune it anyway right?

craig · Sep 24, 2005

Hey John!!!! Good to talk at ya!

Anyway, I was under the impression that the 18% grey works best as well. I was also under the impression that only one or two companies actually know how to make them correctly (I will provide links on Tuesday). The custom setting can get messed up by not exposing it properly, so keep that in mind. The ol' Nikon D1H has the standard colour temps plus adjustable tints. For example: I shoot tungsten at tungsten +3 to bring down the cold feel of the standard tungsten setting. I shoot daylight at cloudy +2 for the saturation that it provides. Personally these settings are faster and a little easier to deal with than exposing a grey card. I will bet the 20D has the same options.

Christie Photo · Sep 24, 2005

What I do... I read the grey side to determine exposure. After that, I flip it over and shoot the white side. I want to see the white data on the histogram. I guess I'm just tweeking my exposure. I set the white balance and then do ONE MORE exposure of the white side and reset the white balance.

Now, I must confess... I'm not sure if this is just compulsive behavior, or if it make any difference at all. It seems that with my 10D, I get better results when doing it twice.