White balance: grey or white cards?

[Gymrat76]

A newbie question, but one that I've been in the dark about for a while. Some resources refer to setting custom WB using a white card, while others use the 18% grey card. I used to think grey cards were more for metering, but I've seen a lot of references which use grey cards for WB as well. Can anyone enlighten me?

 

[LittleWolf]

I used to think grey cards were more for metering, but I've seen a lot of references which use grey cards for WB as well. Can anyone enlighten me?

As long as the cards don't have a colour cast, it doesn't matter. White balance deals with the ratio of intensities in the colour channels. A change in brightness affects all channels the same, so the ratio doesn't change.

 

[Del_CtrlnoAlt]

white card is for white balance, 18% grey card is for metering...

 

[HeWolf]

Good question. I've been in the blur for very long, until I chanced upon a chinese site.

White card for WB setting is to restore the original color. So a white object taken until sunset will appear as white.

Grey card for WB setting is to reflect the color as seen when taking the pic.
So a white object when taken until sunset will appear as gold/orange.

 

[Del_CtrlnoAlt]

oh ya forget to add... if u wan some funky color, you can even set your white balance with some color chart color, you will see effects like putting on color filters. its all up to your imagination...

 

[catchlights]

as long the card is neutral in color, same amount of all the RGB value.

 

[Witness]

colour chart.....