Monitor Calibration

By Steve Anchell Back to

steve anchell, monitor calibration, datacolor, photo technique (Left) This is how the image appears on an uncalibrated iMac. (Right) This is how the image appears after calibration.

Do you really need to calibrate your monitor? Perhaps you don’t. Read the following scenarios and see if they fit.

Scenario #1
You’ve just captured the world’s greatest landscape. When you released the shutter the light, color and composition were perfect. Never mind that your camera wasn’t calibrated, you’ll fix it in Lightroom. You work on the image in LR until it’s perfect, color, saturation, contrast, shadow detail, luminous clouds with subtle detail in a blue sky. You write it to disk and take it to a really good lab to print. Never mind that your monitor wasn’t calibrated. The lab can fix that.

When you pick up your print it is darker than it appeared on your screen. And the colors aren’t as saturated. What gives? You ask the lab owner. He shows you the image on his calibrated monitor; it looks exactly like the print. Is your monitor calibrated? He asks.

Scenario #2
You purchase an Epson printer with a K7 inkset. You heard this was the best inkset out there. Now you’ll get a good print. Print #1 is too dark, just like the one from the lab. No problem, you punch up the exposure. Print #2 is better, but the clouds are a little too bright, so you add +60 Recovery for the highlights, and the shadows are, well not quite black enough, so you add +20 Black. In print #3, the clouds are a little gray, and the shadows lack detail, but you’re getting closer. You notice that the sky in the print isn’t the same hue as it is on the screen, and the reds on that pickup truck parked in front of Mt. Shasta just aren’t as saturated as they look on the screen, either. Print #4, add hue and saturation, increase the contrast; while you’re at it add +3 magenta. Print #5, too much contrast, you’ve lost shadow detail; better add some Brightness, or perhaps Fill light; back off the magenta…

By the time you’re finished, somewhere around print #10 or #15, you are ready to accept the variations in color and contrast between what you see on the screen and in the print. Even if the print doesn’t match the original on the monitor it’s every bit as good in its own way, right? After all, nobody will know but you.

If any or all of the above sounds familiar, you need to calibrate your monitor. Monitor calibration requires a reading and measuring device, either a spectrocolorimeter or a spectrophotometer, and software to match. These devices are available, respectively, from either Datacolor or X-Rite. Datacolor calls theirs the Spyder and X-Rite calls theirs the ColorMunki. Datacolor introduced Spyder4 this year and X-Rite introduced their latest version, ColorMunki Display. Both of these are for monitor calibration only, though both companies offer complete calibration packages, which include both monitor and printer calibration devices and software.

Datacolor has learning videos on their site and X-Rite has a series of webinars on color management and calibration. You do not have to own or use their product to benefit from the wealth of information on both these sites.

I have been using the Datacolor Spyder since version 2. For this demonstration I will be using the Spyder4 ELITE, which has the most complete set of controls in the Spyder lineup for custom calibration. However, both devices, Spyder4 and ColorMunki, work equally well.

Monitor calibration is as much about contrast and brightness as it is about color. For that reason it is important to adjust the ambient light levels surrounding your workspace. The higher the ambient light the brighter your screen will need to be, and the lower the apparent contrast. This will impair your ability to visually judge contrast (think of the LCD screen on the back of your camera; in low light you can turn down the brightness to conserve battery power, but in bright sunlight you need to turn it all the way up in order to see the image).

Spyder4 software opens with a checklist of things to do prior to calibration. The first is to be certain your screen is warmed up for at least 30 minutes.

steve anchell, monitor calibration, datacolor, photo technique
(Figure 1) Begin your first full calibration (FullCAL) using the recommended defaults. At the bottom of the dialog box is a link to Advanced Settings, also known as the Expert Console. Go to the Expert Console and make certain the Ambient Light test is enabled (see Figure 2).
steve anchell, monitor calibration, datacolor, photo technique
(Figure 2) Ambient Light test is enabled. Return to the Basic Settings Wizard.

The second is to check that no intense light is falling directly on your screen. Whether it is or not, it is always a good idea to use a monitor hood to reduce eye strain, aid in consistent color calibration accuracy, and reduce flare from doors and windows. You can purchase monitor hoods online for any size LCD screen from photodon.com or you can make your own from black foam core and tape. It should have a depth of about 8″ and completely cover the sides and top of the screen (the bottom can be left open). In my homemade foam core hood I have cut a whole large enough to drop the Spyder calibration device through.

The third is to reset your monitor settings to their default before beginning calibration for the first time (once your monitor has been fully calibrated the first time it is usually only necessary to do a recalibration; this means you do not have to reset the defaults before each calibration).

If you are using a professional quality monitor, such as the LaCie 324i, you will have access to external controls on the monitor itself.

However, an increasing number of photographers are using either laptops or Macs which use software controls for brightness, with no control over contrast. Using Windows 7, go to Control Panel > Display > Adjust Brightness (Power Option). At the bottom of the dialog there is a brightness adjustment. Move it all the way to the right before beginning calibration for the f irst time (it should not need to be reset for re-calibrations).

On a Mac go to System Preferences > Display. Set the brightness slider in the center. Finally, make certain the device is plugged into a powered USB outlet. Click ‘Next.’

At this point you have the choice of using the Step-by-Step Assistant, (Figure 1) or the Expert Console. The primary reason to use the Expert Console, is to manually change the Black Luminance value. Everything else can be changed in Calibration Settings.

My suggestion is to start with the recommended defaults the first time through (Gamma: 2.2; White Point: 6500K; Brightness: 120). If you feel you need more control you can switch to the Expert Console (see the sidebar, White Point, Gamma, Black Luminance, White Luminance).

The first time through the process you will want to do a full calibration. Always start a full calibration with an ambient light check. At the bottom of Calibration Settings is an Advanced Settings option. In the Advanced Calibration Settings dialog be certain that Ambient Light is turned on (Figure 2). Return to the Basic Settings and click on ‘Next.’

To check the ambient light you will need to place the Spyder4 device in its cradle in front of the screen (Figure 3). Ideally, the results will read that the light is within a medium range. If so, continue. If not, take the appropriate steps to adjust the ambient light or shield the display, then retest. If you cannot bring the ambient light to a medium setting, then accept Spyder4’s recommended settings (see White Luminance sidebar).

steve anchell, monitor calibration, datacolor, photo technique
Figure 3) Try to get the ambient light level to where the result reads ‘medium.’ You may find that the default settings have been changed. In this case the recommended White Point is still 6500K but the recommended White Luminance value has been set at 180.
steve anchell, monitor calibration, datacolor, photo technique
After reading the ambient light Spyder4 recommended a White Luminance value of 180.0. The Spyder4 photocolorimeter read 174.0. Clicking on the Apple icon at the upper left of the Mac screen allowed the choice of System Preferences>Display. In Display I was able to move the Brightness slider to the right and update the reading until it was 181, within the allowed 4% tolerance.

‘Next’ brings you to the calibration screen. You’ll need to remove the measuring device from its cradle and hang it over the top of the display; adjust the counterbalance to hold it in place. Be certain the screen is tilted back slightly so that the sensor is flush against the screen and no stray light can get between. Click ‘Next’ to begin calibration.

The calibration process will pause when it comes to the White Luminance (brightness) screen. (Figure 4). On the right side of the white target it will display the target brightness, the higher the value the brighter the screen. Below that is the measured brightness of the screen. If the measured brightness is within 4% of the target, click ‘Continue.’ If not then this is where you readjust the brightness you previously set to its default. If your monitor has manual controls, use these to adjust the brightness. If not, use the software controls built into the operating system.

With a Mac click on the Apple icon and go to System Preferences > Display and move the Brightness slider; left to reduce brightness, right to increase. Unfortunately, the slider is not calibrated so it is a hit-or-miss thing. Back on the White Luminance screen click on Update at lower right.

Give the Spyder a moment to read the new value and then check it on the screen next to ‘Current.’ Readjust as needed until you are within the 4% range, then click ‘Continue.’

With Windows 7, follow the same procedure through the (Start > Control Panel > Display), using the Brightness setting to make the luminance adjustment.

The rest is automatic until the end. When you see the Save Prof ile screen you can accept the default name (Apple iMac-1) or change it to something more meaningful. I like to add the date of the calibration. Out-of-date calibrations can be deleted at any time (Figure 5).

steve anchell, monitor calibration, datacolor, photo technique
steve anchell, monitor calibration, datacolor, photo technique

(Figure 6) The final screen is a soft proof of the calibrated screen. You can switch between before and after at the lower right side. Notice that the color and brightness change over the entire screen, not just the test image.

steve anchell, monitor calibration, datacolor, photo technique

(Left) This is how the image appears on an uncalibrated iMac. (Right) This is how the image appears after calibration.

When calibration is complete you will be prompted to accept the default name (Apple iMac-1) or customizing the name to something more meaningful. I add the date at the end and get rid of the Apple for brevity (iMac-1-02012012). Don’t leave any spaces between letters, numbers, or symbols.

Now that your monitor is calibrated you need to keep it calibrated. For me, that means calibrating at the beginning of every month (easy to remember), or before I process an important project. In other words, I usually end up calibrating every few weeks. In any event, I set the reminder at one month, though I rarely make it that long without recalibrating.

The final screen is a soft proof. The first time I used Spyder I wondered if this was really a before-and-after image or if Datacolor had simply inserted an out-of-calibration image to make the new one look good. Then I noticed that the color and brightness on the screen changed along with the before and after image in the dialog box. Now I’m mostly convinced. So, the question: Do you really need to calibrate your monitor? The answer is actually quite simple. Do you take control of the process, or do you allow the process to control you?

Gamma, White Point, Black Luminance & White Luminance
These are the four values we use when calibrating a screen. They are affected by the level of ambient light and the quality of the screen. Better monitors have higher definition and are generally of lower contrast. If you are not able to reach a medium light level, Spyder4ELITE will recommend a new target value for White Point and White Luminance. These four values are easily understood.

Gamma: Although it is an entire course of study to fully understand gamma and to plot gamma curves, for our purposes gamma is simply a measure of contrast. The higher the gamma the higher the contrast. By contrast is meant the number of gray tones between the lightest areas and the darkest areas. The more gray tones the lower the contrast. If the contrast is too low, the image appears to be flat, lacking pizazz, for want of a better word. If the contrast is too high the image loses detail in the shadows and highlights. With a medium level of light and almost any good quality monitor made today, a gamma of 2.2 is typically chosen. If the ambient light is too high it will lower the screens apparent contrast, and a higher gamma, such as 2.4, should be used.

White Point: Is the color temperature of the monitor. This is also affected by the ambient light level. White Point is also affected by the color space. A color space using Adobe RGB (1998), most often used in Photoshop and Lightroom, uses a color temperature of 6500K. For this reason we generally select a White Point of 6500K. However, if the room light is too low, it is often better to lower the color temperature to 5800K. Whenever possible, it is better to raise the ambient light level.

Black Luminance: Is a measure of the blackest black on the screen. A value of 0.0 would be as black as the screen can get, but a black luminance value of 0.0 will invariably result in lack of shadow detail on the screen, resulting in overcompensation, resulting in low contrast blacks on the print. A black luminance level between 0.2 and 0.3 is preferred. However, unless you are using a high-end display you may have to rely on the color calibration device and software to set the black luminance value.

White Luminance: Measures the screen brightness. The preferred brightness level is very much affected by the ambient light level. If the ambient light is too high the screen needs to be brighter. If too low, the screen needs to be darker. In a medium level of ambient light the White Luminance value should be set around 170 to 180; in low levels between 120 and 130; in high levels 200 to 220. However, because light is transmitted through the image on the screen and reflected off the surface of the print, there are some who prefer to use a lower White Luminance, around 90, which more accurately simulates what the image will look like on paper. This is a perfectly good working method but in order to make the best use of this technique the ambient light should be lower than medium and the White Point lowered to 5800K. I will personally guarantee that eye strain and fatigue will result.

Resources: Datacolor: datacolor.com, spyder.datacolor.com; Photodon: photodon.com; X-Rite: xritephoto.com, xritephoto.com/ph_learning.aspx?action=webinars; LaCie: lacie.com


About the Author

Steve Anchell
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Steve Anchell is an internationally published photographer, teacher and writer. His books The Darkroom Cookbook, The Variable Contrast Printing Manual and The Film Developing Cookbook are international photography bestsellers. steveanchell.com