Saturday, August 20, 2011

The Second Step to Digital Image Excellence

So, you've bought that Nikon® digital camera you've wanted for a while. The first step is complete! What is step number two? Get a printer? Nope! Step two is to buy a monitor calibration system. Especially if you shoot RAW (NEF) images!

Why is that the second step to digital excellence? Well, it all boils down to a capability our human brain has that can hinder our ability to process accurate color images in our computers, after the fact. "What is that capability," you might ask? Our brains are selective and adaptive. Our cameras are not nearly so powerful. What I am talking about is simply this—when you walk into a room from outside and see a family member reading a book under a tungsten lamp, what color are the book's pages to you? White, right? "Yes," you may say, "but, so what?" Well, if you took a picture of the book under the lamp light, those "white" pages would have a strong orange color from the tungsten light. Your brain sees white, even though the light is truly not white. Your incredible brain has automatic white balancing! That's a real problem for photographers.

Following is a sample night-time image that I took recently. It has about four types of lighting in the image. I was doing time exposures while waiting for a nice lightning strike. It was storming while I stood on the front porch with my Nikon on a tripod. When I looked at the scene, I saw nice white lights, and finally a small lightning strike in the background. However, when I pulled the image up on my computer later, I was amazed to find weird light sources and color casts.

A night-time image with "colorful" lighting

The light on the left is yellow, the middle one is white, the right one is green, and the sky is bluish. But, my brain only saw white lights. Had I really taken the time to look, I'm sure I would have noticed the color casts, but the point is, I would have had to force myself to think about it carefully and turn off my brain's automatic white balance before I would see the different colors. My brain, and yours, automatically balances light sources in a way that no camera ever will. That, my friend, is a problem!

As you sit down with your monitor that you see everyday, you don't notice any color casts, do you? Your brain has grown accustomed to the colors of your screen. But, unless your monitor has been calibrated, it is likely not accurate and viewing your carefully created images on it will not show them correctly. You might feel that an image you took is too warm, or has too much red, when in fact, it is balanced correctly. When you open an image and start looking for color casts, you've turned off your brain's automatic system for a few minutes, without thinking about it. But, since you've grown accustomed to the standard colors your monitor displays, you may be seeing a color cast in your images that are not really there.

Basically, it boils down to this question: Can I trust my camera's white balance in all instances? No, you can't! It can only create consistent color if you are shooting in one light type that never varies, or constantly adjusting the white balance to the light in which you are shooting the pictures. If you aren't doing that, you may be introducing color casts during post-processing and your monitor will not tell you the truth when it shows them to you.

Are you really sure the green cast you removed from that last image was really there? How do you know? What if the picture was accurate and you removed green? Your image will show a blue or red color cast on other people’s more balanced monitors, while on your unbalanced monitor it may look perfectly correct. If you are really concerned about the quality of your images, shouldn't you think seriously about calibrating your monitor?

I calibrate my monitor every two weeks. Some do it weekly or even daily. Why? Unless you've been calibrating monitors regularly you would be surprised how far off the color balance can get in only a few days. Your monitor displays color in three channels called RGB for red, green, and blue. Each of these channels are individually balanced to input a certain set value of that color. The combination of different levels of RGB make up all the colors your monitor can produce. But, what if the individually adjustable red channel is too high, or the blue, or green? Your brain will adjust in a short time to the unbalance and see everything as just right. Then when you open an image and are looking for color casts, your brain may be fooled into seeing something that's not really there. In only a few days after calibration, your monitor's RGB color channels will drift slightly and introduce a slight color cast into your images. I didn't realize this until I started regularly calibrating. Now, I calibrate faithfully.

The solution is to buy a low-cost monitor calibration system. My favorite is the Datacolor® Spyder 3 Pro color meter and software. It runs about US$110 for a complete hardware/software package that will keep your monitor in top calibration, with all the RGB channels in exact balance, and brightness under control. Only then will you have an accurate display of your excellent images.

Besides Datacolor, there are several other monitor calibration vendors that offer reasonable or even lower prices. Considering the low cost, there is little excuse for not having a calibrated and profiled monitor to accurately show your images. Think about how much you've paid for your highly-calibrated Nikon DSLR and its excellent lenses. Why spend all that money on premium camera hardware, shoot great images, and then post-process your RAW images on an non-calibrated monitor.

When it comes time to print, you'll find it much easier to get good results if your monitor is calibrated. When I first started trying to print digital images with my inkjet printer, I was coming up with some very funny looking colors. I spent considerable time and money trying to understand why my images printed too green, or too red, when they looked fine on my monitor. I almost gave up and went back to the commercial labs; however, I started doing some research instead and read up on the problems that result from an unbalanced monitor. When I bought my Spyder 3 Pro system, I was simply amazed at how far off my expensive 20 inch flat screen display was. After I calibrated the monitor, and created a profile, I found it was much easier to print nice color-balanced pictures.

This information applies to any type of monitor, especially older CRT types. Even LCD (TFT) displays need to be balanced. Any time you are working with color spaces and converting between different devices like cameras, monitors, and printers, it is always best to have color profiles that help keep the colors close to what you expect. It isn't perfect, but it sure beats making 12 prints to get one with good color balance!

For about US$100 (or less) you can own a monitor calibration and profiling system that complements your expensive Nikon camera. Why take chances with your monitor's color balance? Get yourself some color insurance. Go buy or borrow a monitor calibration system and profile your monitor. You'll then see what you've been missing all along. If you are like me, you won't believe it until you see it. But, once you do, you'll never go back to the old way.

Keep on capturing time...
Darrell Young

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