18% grey or white card for white balance setting

[Christie Photo]

why is it not a good idea to use black card?....i'm just trying to understand the physics i hope you dont mind

Black means no light reflecting. So.... no light, no data to read.

 

[shingfan]

A grey card reflects 18% of the light falling onto it. The back of a grey card is white. I always shoot both... grey side first. The card should fill the entire image. After shooting the grey card and setting my exposure, I set the white balance. I then shoot the white side and double-check my exposure. I look for a thin line on the histogram, straight up and down, all the way to the right but not going off the graph. Once I have achieved this, I reset the white balance.

Maybe I'm an obsessive-compulsive type.

Pete

i like this method very much....very scientific....as you can see...i'm more of a science guy

what do you mean by resetting the white balance after you already adjust it with the grey card?....what do you reset it to?...this part i dont quite understand...i understand that you use the grey card to set hte white balance and use the white side and histogram to verify....not sure what the reset is for if everything checks fine?

 

[Christie Photo]

One more thought.... light metes tell you how to achieve grey. That's why we meter a grey card to determine exposure.

 

[Christie Photo]

what do you mean by resetting the white balance after you already adjust it with the grey card?....what do you reset it to?...

It's just something I do. I do everything twice. It's not the quickest way to live my life, but I HOPE it protects me from SOME of my stupid mistakes.

Pete

 

[shingfan]

o.....you mean you do this sequence twice to make sure things are okay and then you just reset to the previously captured white balance setting ....i see

so i guess a grey card is highly appreciated?.....

 

[markc]

I personally prefer white over grey for balance. I'm sure a light grey works just fine in most situations as long as it's neutral, but the closer to black you get, the less light are are having reflected to work from. If you have a dim exposure you might run into issues.