A recent article demonstrated how to color match strobes essentially by purchasing an overpriced light meter for $1200. There is a much easier way to do this using Camera Raw. The only catch is you’ll need to bring your laptop to a shoot with you (or use my new White Balance Meter app from the App Store).
First step, before you go on site, and you only need to do this once: shoot a gray card with flash and no gels, using a non auto white balance. Load the pic into Camera Raw. This is especially quick if you use an Eye Fi. Click the white balance tool then click the gray card. You’ll see the temp and tint sliders change.
If you shot in raw, you’ll see the actual color temperature represented here. If JPG, then you’ll see +/- sliders.
Make note of these offsets; these are the offsets for your room so you’ll need to factor those into the results. Now shoot gray cards with each gel on the flash. Load these images into Camera Raw and measure their +/- temp and tint values. You now have the difference between the gels and the bare flash, and you also can correct each one to account for the difference between bare flash and the room. So if the bare flash corrected to +10, and your gel corrected to -10, then you know that gel has a temperature -20 offset the bare flash. Write these offsets down on each gel.
When you’re on site, shoot a gray card bare flash and load it into Camera Raw. If you’re using an Eye Fi you can set up an ad hoc network and do this without even turning off your camera. Click the gray card with the white balance tool. Now all you need to do is add the gels to total the offset correctly and your strobes will match the room. You also just saved $1200 not buying the overpriced light meter advertised.
Camera Raw measures temp and tint on its own scale instead of by Kelvin. That’s just fine. You’re measuring offsets here so as long as you are consistent with your measurements, the math still works.
New! White Balance Meter is now available in the App Store, designed to help you accomplish this same technique without spending a ton of money on gear.