The newest addition to my camera bag is the X-rite ColorChecker Passport. The ColorChecker is a basically a gray card on steroids. Not only does it have a panel with a gray card for creating a custom white balance, it also has several dyed and calibrated reference colors to use with the accompanying software.
The software then takes the squares of color and creates a custom camera profile in LightRoom to correct for any color casts or other color issues.
For instance, you can correct for a color cast in an image using a custom white balance, still, even at a neutral tone, your camera may not have recorded the blue or the red as accurately as it appears on the card. The ColorChecker then corrects for this. So, in essence, using a ColorChecker will get all your colors extremely accurate, better than what you could do this quickly by hand with curves or something similar.
To me this piece of hardware is worth its weight in gold. My monitor is calibrated for accurate color so why shouldn’t my camera? The ColorChecker does this for me. I love using anything that eliminates variables when I’m editing so I know that a change I make is only on the screen and in the file, not generated from my camera or from the monitor.
For years I’ve used a colorimeter to calibrate my monitor and now I can rest assured that my camera is producing the most accurate colors as possible when I start post processing.
At less than $100 on Amazon there’s no reason any imaging professional should not have one of these especially if a camera is involved at any point in the process.