Raise your hand if the colors in your photos never look quite right. Wow, that’s a lot of hands! It seems there’s never a shortage of forums with discussions about light boxes, and light bulbs, and bluish tints, and weird pink and green color casts. In some of my earlier posts, I told you how easy it was to get great photos, with realistic colors, in natural lighting. But yes, I do understand that shooting in natural light isn’t always practical. Many of us, therefore, resort to shooting indoors with all kinds of artificial lighting, and experience a wide range of color problems. So in this post I’m going to talk about an easy way to get those colors right, each and every time, using a simple “gray card.”
Very briefly, a “gray card” (at least the one we’ll be talking about) is in fact the color gray. But more importantly, it is “spectrally flat,” meaning that it has a fixed reflectance (18%) over the visible part of the spectrum. That means that all wavelengths of visible light (basically, the rainbow) are reflected in the same amount. Film photographers have used them for many years to help set their exposure properly, and they can still be used for that purpose with digital cameras (but that’s not why we’re here right now). Okay, enough of that nonsense, let’s get started. Most of this post is going to cover how I did the test to get the photo examples. If you’re not interested in any of this, and just want to see what you need to do to use a gray card to your advantage, skip down to the “You can do it, too” section.
For my example, I decided to use a thank you card that we recently received in the mail. The face of the card is primarily a soft off-white color with red and pink flowers. I put it in my homemade light box and lit it with a single lamp from above. I first used one of those “daylight fluorescent” bulbs with a “color temperature” of 6500K written plainly on the label. Don’t worry, you don’t need to know anything about color temperature – I’m just explaining what I did so you can follow along. I then set my camera’s white balance to “auto,” took my first shot, and here’s what I got:
It’s not bad, but it’s a little on the blue side. I know there’s no way for you to see for yourself, so you just have to trust me – when I look at this image and the card side-by-side, the image definitely has a slight bluish tint.
Next, since I knew exactly what kind of light I was dealing with, I set my camera’s white balance to “daylight fluorescent” to match the lighting. Makes perfect sense, right? Not so fast – here’s what I got:
That is one weird photo. The colors aren’t even close! As my wife pointed out, it’s not a bad color – it’s just that it’s all wrong.
Now, the magic of the gray card. I put it in the light box in place of the thank you card, set my camera’s white balance to “custom”, aimed at the gray card and click, I captured my custom white balance. I removed the gray card from the scene, took another shot of the thank you card, and voila, here’s the result:
Now this one looks just like the real thing! So I saved my custom white balance setting, knowing that in the future if I ever want to shoot with the same type of light I can just use this setting and I’ll get accurate colors.
Now on to round 2. Without changing anything else, I replaced the “daylight fluorescent” light with a “soft white” incandescent bulb (color temperature about 3000K). I put my camera’s white balance back in “auto,” took another shot, and got this disaster:
Yuck! Yellow, brown, tan, whatever you want to call it. I just know it ain’t white! So I figured I’d give it another chance, this time using the “incandescent” white balance setting on my camera. And here’s what I got:
Better – definitely less yellowish, but now it has a bit of a pinkish tint. Pretty enough, but it’s not the real color. So it’s back to the gray card one more time (remember, the only thing I changed in the setup was the type of light). I used the same procedure to set my new “custom” white balance, and this is the result:
Remarkable, isn’t it? Again, it looks just like the real thing. Two photos (the 3rd and 6th), taken under two completely different types of lighting, made to look exactly the same by simply using a gray card. And it was easy – in fact…
You can do it, too
- Make sure your camera has a custom white balance feature. Check the index in your user manual for something like “White Balance” and then “Custom.”
- Get yourself a gray card. When you look in your camera’s manual, you’ll probably see that you can set your custom white balance by using any white surface. That’s a bit misleading. The truth is, any spectrally flat surface will work, but not all whites meet this requirement. Worse yet, you don’t know if the one you chose is or isn’t spectrally flat, so you don’t know if you can or can’t trust it. Just compare a few different types of “white” paper side-by-side and see how different they look. You’re better off going with a gray card specifically manufactured for this purpose. You can get one at a variety of shops selling photography gear, or you can pick one up in the “Supplies” section of my Etsy shop.
- Place your new gray card in the same location as the item that you will be shooting. It doesn’t matter if it’s a light box, or a table, or on the floor, or outside on your patio. Just make sure you’re using the same lighting as you will for your photos.
- Follow the steps in your camera’s manual to tell you how to capture a custom white balance setting. It’s usually just a two or three step process, and once you do it a few times you’ll find that it’s really easy to do. Just make sure that the entire image is taken up with the gray card when you do the capture.
- Using your new custom white balance setting, take your photos and be amazed at the accuracy of the colors!
There is another way that gray cards can be used to correct colors during post-processing with some photo editing software, but we’ll save that one for later.
Until then … Happy Shooting!