Does gray card a necessary tool in photography? Do you have any gray card with you? I do. I have Mennon Gray Cards. However, I did not use it much since I bought it.
Mennon Gray Cards
The Mennon Gray Cards package that I bought consist 2 gray cards. They are 8×6″ and 10×8″ sizes. I did use 8×6″ gray card once in a while. But I did not use 10×8″ at all because it is too big to carry along.
8×6″ and 10×8″ Mennon Gray Cards
So what does gray card do? It will correct your photo white balance. Just look at the photo below.
White balance corrected with gray card
As you can see, the first photo is warmer than the second one. The warm lighting is causing the photo to look warm. However, by using gray card, we can correct the white balance of the photo.