In photography, we use a gray card which helps to set accurate white balance for the giving lighting conditions. A few years back, I received a fairly small gray card for Christmas. However, it’s made out of thin cardboard-type material, so I’m cautious about how I carry it because I don’t want it to break.
I’ve often considered cutting it down to a smaller size and punching a hole in it so I can attach it to my keychain. However, it was a $40 gray card, and I’m just not about cutting a $40 card in half.
As such, I’ve hardly used it because I keep it so heavily packaged; it’s really an ordeal to get to and to use.
I was watching one of my favorite podcasts today and they mentioned a series of WhiBal cards that are available in a range of sizes, including a size for keychains. It even included a small S caribiner!
I was able to use my NAPP discount to get one of these guys for $16, which is a great deal (in my mind).
Now, I will always have this with me, easily accessible, and just have to make sure I capture it in a photo for any given session in order to quickly and easily set the white balance.