When is a colour card not a colour card – Grey Cards

how not to set white balance

I see on the forums, YouTube and general internet sources a lot of confusion about setting a custom white balance.

Custom Profile

The main issue I see is that people are setting colour white balance using a grey card. This is potentially wrong. A grey card is calibrated 18% grey in order for you to get your metering correct. A colour checker card to set white balance has a neutral grey or white, ie the red green and blue channels are balanced.

Now you can buy 18% grey neutral grey cards, so these can be used for exposure and for setting white balance, but do not assume a grey card is neutral!

How to use also generates some debate. First thing is to get the lighting and exposure right. In the top picture, I was setting a fairly simple lighting set up. I had the model hold my colour balanced grey card white I tweaked the lighting and exposure. Do not take the white balance reading until you are setup, changing the lights and exposure can change the white balance. The picture here has a number of issues, but the biggest is that the cheap studio provided trigger is not syncing correctly with my camera thus the dark area at the bottom.

Step one, setup your shot, get the lighting, exposure all how you want.

Step two, take a photo of the subject with the colour checker, white balance card in the shot.

Step three – this is where we have some debate and it does not really matter. Either set a custom white balance using that shot in camera so that all your future shots are correct, or in your tethering software so everything looks correct. Or after the shoot most RAW software allows you to sync the corrected balance that shot to the other shots. Generally you edit that shot, do a custom white balance using the card in the shot, then sync the white balance settings across the other shots.

One last thing to consider; if like me you have custom import profiles that set a particular look, these may overwrite the colour balance, as may any other development profile you apply.

Oh and we are talking RAW, JPG bakes the colour temp into the file, it needs to be right.

What do I use and how? Well I have a couple of small white balance cards scattered across several camera bags as well as a A4 colour checker in my largest bag, so I always have something with me. As to how I use, well its naughty of me but I am not consistent.

When doing a shoot I am often in a manual white balance setting, using a card for important shots, then syncing things up at the end. It is an area I need to improve on.

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