Sign in with
Sign up | Sign in

Application: How To Adjust Levels

Display Calibration 201: The Science Behind Tuning Your Monitor
By

Hopefully, all of this talk of science and theory is inspiring you to try calibrating your own display. If you have the basic tools available, you can do this by following the steps we’ll outline in the next four pages. As stated in the beginning, you’ll be adjusting the monitor’s controls only. This method does not use a software look-up table. You can also create an ICC profile for use with your graphics apps. We’ll show you how on page nine.

We suggest you follow the steps here in the order we give them. Since there are nearly always interactions between controls, this procedure minimizes the need to go back and forth to dial in your display.

First, you should go through a little pre-flight drill.

  1. Warm up your monitor for at least 30 minutes before you start. That way, the backlight will be stable and you’ll get the most accurate measurements.
  2. Find a picture mode that is neither too bright nor too dark. Usually one marked Standard is a good bet.
  3. Set the Color Temp to User or Custom so you have access to the RGB sliders.
  4. If there is a Gamma preset, choose 2.2.
  5. Now you’re ready to begin.

First up are the level adjustments; Brightness and Contrast. These can be set by using a couple of test patterns. There are many available that will work. Here are a couple of samples.

This is one of the grayscale step patterns generated by our Accupel. You can also find this pattern online. In fact, we downloaded this very graphic. You should see 11 brightness steps. Fifty percent is in the middle.

Here is a PLUGE pattern.

PLUGE is a traditional term for patterns used to set levels. The acronym stands for Picture Line Up Generating Equipment. Definitely a throwback to the analog era! You should be able to see four vertical bars in the center of the field. They start with the darkest on the left and become brighter as you go right.

This pattern is good for setting contrast.

We’ll explain how to use all of these patterns in a moment. The important part is the section on the right side. There are a total of 33 bars ranging from 0 to 100 percent, or in RGB terms, 0 to 255.

Finally, we have another pattern that’s even better for setting contrast.

In this pattern, you should see eight concentric squares that vary in brightness. If you can’t see all eight squares, that color is clipping.

The common theme in all of the patterns is that they have bars a few brightness steps apart from one another. By viewing these bars, it’s easy to see when you’ve set the controls too far in one direction because one or more of them blend together. This is what we mean when we use the term clipping.

Start with the first pattern, the grayscale steps. Lower the Brightness control until the darkest two bars become one. On most monitors, they’ll never actually blend because they’re quite far apart in brightness.

Now try the same exercise with the second pattern. On some monitors, the darkest bar will disappear. When this happens, turn Brightness back up until the bar is just visible. If you can turn your Brightness control all the way down without clipping any bars, then you should set the control with a meter instead. Display a 100 percent window pattern like this one.

Measure the window with your meter and adjust brightness until it’s at the value you want. We always use 200 cd/m2 but your preference may vary based on your room lighting conditions.

Now display the third pattern. Raise the Contrast control until the rightmost two bars blend together. That’s your clipping point. If you can raise it all the way and the bars are still visible, try the fourth pattern with the colored squares. This one is more precise because you can see the clipping point of each primary color. If one color clips, you’ll lose grayscale accuracy because the monitor has literally “run out” of that color. We’ve noted in all our monitor reviews that the Contrast control’s default setting is usually at its highest possible point. Raising it even one click often clips at least one color and sometimes all of them.

This is pretty easy to do, even without a meter. Most monitors will let you set the brightness anywhere in their range without clipping blacks. You just have to decide how bright you want your screen to be for your particular workspace. And contrast is generally fine at its default setting.

Since the final values of your level adjustments determine the measurement parameters for gamma, it’s important to do this step first. As we’ve already demonstrated, poor gamma has an obvious negative impact on image quality.

Ask a Category Expert

Create a new thread in the Reviews comments forum about this subject

Example: Notebook, Android, SSD hard drive

Display all 26 comments.
This thread is closed for comments
  • 8 Hide
    expl0itfinder , October 13, 2013 9:31 PM
    Interesting article. Very detailed and well written. Kudos to the author.
  • -4 Hide
    MANOFKRYPTONAK , October 13, 2013 10:25 PM
    For TVs CNET posts the color levels they use to test each TVs picture by model. They also give great advice on how to adjust too! I used there settings with my 50" vizio and could not be happier. Don't get me wrong loved this article, but you can never get too much info, am I right?
  • -2 Hide
    yolosweg , October 13, 2013 10:37 PM
    I've adjusted the gamma on my laptop but it keeps reseting. Does anyone know how to fix this? (I used the default windows program btw)
  • 0 Hide
    Vladimir83 , October 13, 2013 11:11 PM
    Fantastic article.....TomsHardware style!
    I have no idea how my monitor was off until i saw the patterns ;) 
    Now perfectly set for brightness/contrast:first,third,and fourth pattern(although on this i notice cliping on the blue).
    However second pattern couldn't set it right.Darkest bar which should be almost cliping to the background is too "black",and the next "12" bar is more closely match to the background in colour.
    Any thoughts someone? I use Philips 227Eqha IPS monitor.
  • 2 Hide
    rezzahd , October 14, 2013 8:08 AM
    Great display calibration guide. I would recommend this to anyone new to display calibration.
  • 1 Hide
    clonazepam , October 14, 2013 10:48 AM
    Every time I took a support call for pro graphics products, and it centered around getting accurate color, I started off with "Color is a 3-dimensional space..." It was just my way of saying we might be here for awhile.

    I love these articles. =)
  • 0 Hide
    ojas , October 14, 2013 11:19 AM
    Second page, second last photo, article should say that you've set the black level too low, not too high.

    Seems to be an interesting read so far, and I've really wanted to read an article like this, so thanks in advance!
  • 0 Hide
    ojas , October 14, 2013 11:30 AM
    Doesn't the first picture of Gavin on the 3rd page have low gamma and the second bright one is where the gamma is too high?

    It's written the other (incorrect?) way around in the article, i think.
  • 0 Hide
    ojas , October 14, 2013 11:56 AM
    Quote:
    Now we’ll make the color temp too warm; in other words, below D65.


    Shouldn't it be "above D65"? :/ 
  • 0 Hide
    gwolfman , October 14, 2013 1:04 PM
    Quote:
    Doesn't the first picture of Gavin on the 3rd page have low gamma and the second bright one is where the gamma is too high?

    It's written the other (incorrect?) way around in the article, i think.
    It's opposite. Lower gamma makes the dark areas of an image brighter, hence the entire picture looks brighter. Higher gamma makes the lighter areas darker (i.e., it takes a lot brighter white in the image data to actually be displayed white). Check here for a great tutorial on gamma, especially the section titled "Display Gamma."
    http://www.cambridgeincolour.com/tutorials/gamma-correction.htm


    Quote:
    Quote:
    Now we’ll make the color temp too warm; in other words, below D65.
    Shouldn't it be "above D65"? :/ 

    That's incorrect. It actually works backwards/opposite from what one might think. Color temperature originates from the color a flame radiates in relation to the temperature at which it burns. Think back to grade school and playing with the Bunsen burner... the hottest part of the flame (i.e., higher Kelvin) is in the darkest blues, not the reds (i.e, lower temperature/Kelvin). This simple picture helps explain the difference.

  • 0 Hide
    Fokissed , October 14, 2013 1:08 PM
    Quote:
    Quote:
    Now we’ll make the color temp too warm; in other words, below D65.


    Shouldn't it be "above D65"? :/ 


    Warm (reddish) colors are below 6500K, whereas cool (bluish) colors are above 6500K.
  • 1 Hide
    PhilFrisbie , October 14, 2013 1:10 PM
    Quote:
    I've adjusted the gamma on my laptop but it keeps reseting. Does anyone know how to fix this? (I used the default windows program btw)


    Try installing a full featured driver from your video hardware manufacturer.
  • 0 Hide
    gwolfman , October 14, 2013 1:14 PM
    The author of the article stated:
    Quote:
    We always measure color gamut and luminance in our monitor reviews, even though those parameters are not adjustable in most cases.

    But don't most monitors have a "backlight" option which changes how bright the image without adjusting the contrast & brightness? This can used to effectively adjust liminance, but at superficial global adjustment level rather than a granular control. None the less, one can then put preference on the brighter or darker end depending on their use case(s).
  • 0 Hide
    ceberle , October 14, 2013 3:18 PM
    Thanks for your questions about gamma and color temperature. It seems counterintuitive to say that lower gamma produces higher brightness but that is indeed the case. The lower the value, the higher the brightness.

    Grayscale can be confusing too. As the temperature gets lower, the color is said to get warmer.

    Ojas, the photo on page 2 showing a higher black level is correct. As you raise the black level, blacks get brighter and become more gray.

    -Christian-
  • 1 Hide
    ceberle , October 14, 2013 3:22 PM
    Quote:
    The author of the article stated:
    Quote:
    We always measure color gamut and luminance in our monitor reviews, even though those parameters are not adjustable in most cases.

    But don't most monitors have a "backlight" option which changes how bright the image without adjusting the contrast & brightness? This can used to effectively adjust liminance, but at superficial global adjustment level rather than a granular control. None the less, one can then put preference on the brighter or darker end depending on their use case(s).


    Unfortunately, very few monitors have separate backlight and brightness controls. None of the screens we've covered this year (16 including reviews not published yet) have a backlight control. This kind of thing is common on HDTVs but not computer monitors and that is a shame. With brighter screens, it's really nice to be able to move the dynamic range up or down to get better blacks or brighter whites, depending on application.

    -Christian-
  • 1 Hide
    Shankovich , October 14, 2013 5:50 PM
    Another great article to put in my references, this is why I love Tom's
  • 1 Hide
    jeffredo , October 15, 2013 1:33 AM
    I just broke down and invested in a Spyder 4 Elite colormeter.
  • 0 Hide
    kevith , October 15, 2013 3:32 AM
    My monitor looks the same no matter what of this I try. And the conclusion is, as in the case of every "adjust-your-monitor-in-an-amazing-small-number-of-steps" article I ever read: Go buy the hardware thingy or forget it.
  • 0 Hide
    ojas , October 15, 2013 4:13 AM
    Quote:
    Quote:
    Doesn't the first picture of Gavin on the 3rd page have low gamma and the second bright one is where the gamma is too high?

    It's written the other (incorrect?) way around in the article, i think.
    It's opposite. Lower gamma makes the dark areas of an image brighter, hence the entire picture looks brighter. Higher gamma makes the darker areas even darker (i.e., it takes a lot brighter white in the image data to actually be displayed white). Check here for a great tutorial on gamma, especially the section titled "Display Gamma."
    http://www.cambridgeincolour.com/tutorials/gamma-correction.htm


    Quote:
    Quote:
    Now we’ll make the color temp too warm; in other words, below D65.
    Shouldn't it be "above D65"? :/ 

    That's incorrect. It actually works backwards/opposite from what one might think. Color temperature originates from the color a flame radiates in relation to the temperature at which it burns. Think back to grade school and playing with the Bunsen burner... the hottest part of the flame (i.e., higher Kelvin) is in the darkest blues, not the reds (i.e, lower temperature/Kelvin). This simple picture helps explain the difference.



    Quote:
    Quote:
    Quote:
    Now we’ll make the color temp too warm; in other words, below D65.


    Shouldn't it be "above D65"? :/ 


    Warm (reddish) colors are below 6500K, whereas cool (bluish) colors are above 6500K.


    Quote:
    Thanks for your questions about gamma and color temperature. It seems counterintuitive to say that lower gamma produces higher brightness but that is indeed the case. The lower the value, the higher the brightness.

    Grayscale can be confusing too. As the temperature gets lower, the color is said to get warmer.

    Ojas, the photo on page 2 showing a higher black level is correct. As you raise the black level, blacks get brighter and become more gray.

    -Christian-

    Thanks for clarifying that! I even changed gamma on my monitor to see what happens before i posted, i guess i misinterpreted what was happening.
  • 0 Hide
    Christopher Shaffer , October 15, 2013 12:25 PM
    This is all very interesting and I was excited for a basic how-to until you suddenly said "now get out your meter" but didn't tell me what kind of meter and didn't give me a "parts list" that I'll need to follow your guide.

    That would be very useful, along with some recommendations of affordable "meters".
Display more comments