Color Bars and How To Use ‘em

by Hal Landen

HD Calibration Disk for Monitors, TVs, Displays, Blu-ray Players and more.

Color bars are an artificial electronic signal generated by the camera or by post production equipment. They are recorded at the head of a videotape to provide a consistent reference in post production. They are also used for matching the output of two cameras in a multi-camera shoot and to set up a video monitor.

Before we proceed, you should know that computer monitors are quite different from video monitors and TV sets. You are seeing this on a computer monitor so you will not have the same kind of controls or images as on a video monitor. In fact, if you create graphics on a computer monitor, it’s very easy to be fooled into thinking you have a great looking graphic for your video. But the only real test is when you see that image on a properly adjust video monitor.

The graphics on this page are for example only. You’ll want to use real color bars generated from a camera and viewed on a VIDEO monitor or TV set. Send engineering feedback on this article

To Set up a Video Monitor or TV

1. Allow the monitor to warm up for a few minutes
2. Dim the room lights and block any reflections on the monitor
3. Feed color bars to the monitor either from a camera or “house bars”
from your editing system
4. Set the contrast also called “picture” to its midpoint
5. Turn the chroma also called “color” all the way down until the color bars
are shades of black and white

6. Notice the three narrow bars labeled 3.5, 7.5 and 11.5 on the bottom right. These are the
Pluge Bars which stands for Picture Lineup Generating Equipment. Adjust the brightness control until the middle (7.5 units) pluge bar is not quite visible. The lightest bar on the right (11.5 units) should be barely visible. If it’s not visible, turn the brightness up until it becomes visible.

Since 7.5 units is as dark as video gets, you should not see any difference between the left bar (3.5 units) and the middle bar (7.5 units). There should be no dividing line between these two bars. The only division you should see is between 11.5 and 7.5 (Note this same technique is used in setting the b&w viewfinder on your video camera.)

7. The next step is to set the contrast control for a proper white level. To do so, turn the contrast all the way up. The white (100 unit) bar will bloom and flare. Now turn the contrast down until this white bar just begins to respond. The image below shows what it should look like at this point.

The image below is INCORRECT.

The above image shows a monitor whose black level (brightness) is too high. Of the three pluge bars, only the 11.5 pluge bar should be visible.

NOW for the colors…

First a shortcut to adjusting hue: With a little experience you can avoid the next two steps by simply “eye-balling” the yellow and magenta. The yellow should be a lemon yellow without orange or green. And the magenta should not be red or purple. And you’re done.

But here’s another way: Many professional monitors have a blue-only switch. If your monitor has one, switch it on. If your monitor does not have a blue-only switch, you can use a piece of blue lighting gel. Hold it to your eye like a viewing lens. If you see any of the red, green or yellow colors, double the blue gel over to increase the blue effect.

By using the blue-only switch or a piece of blue gel, you have removed the red and green elements of the picture. Only the blue remains. If the tint and color (also called “hue”) are correct, you should see alternating bars of equal intensity as in the example below. With a little practice, you’ll be able to eye-ball this step fairly precisely.

8. With the blue switch on (or your blue gel in front of your eye) turn the chroma or color until
the grey bar at the far left and the blue bar at the far right are of equal brightness. One trick is to match either the gray or blue bar with its sub-bar.

9. Adjust the hue control until the cyan and magenta bars are also of equal brightness.
You can also match either of them with their sub-bars. Now the four bars – gray, blue, cyan, and magenta should be of equal intensity. The yellow, green and red (which are black in the diagram below) should be completely black.

Here’s a diagram:

Now here’s what it looks like “in color.”

You should now have a properly adjusted video monitor. However, if flesh tones don’t look right, you may need to make further adjustments to the chroma and hue. That’s why engineers say (half jokingly) NTSC means “Never Twice The Same Color.”

Here’s what these same color bars look like on a waveform monitor:

Once you have set up your monitor, leave it alone. Unless you have a waveform and vectorscope, it’s the only instrument you have to see how accurate your video is. This is true of your camera viewfinder, your field monitor and your studio monitor.

---

After you’ve set up a few monitors, you’ll soon know what proper bars look like and then you’ll be able to easily “eye-ball it” with a fair amount of precision. For more information on the video signal, see the engineering article.

But before you get too technical, why not think about making your video business more PROFITABLE!

Also see PAL Color Bars contributed by Sheldon Kennedy.

---

Update: I’m grateful for the many great emails I’ve received about this article. One email resulted in the article being used, with my permission, in a sophisticated defense system. But of all the great email I have received, my favorite was from the Inventor of the Color Bar Generator. I have included that correspondence in a separate article.

14 Comments »

1. 

   What a beautifully concise explanation . If only the author of the DVE set up disc could have learned from you .Thankyou.

   Comment by Nicholas Scott — October 7, 2009 @ 4:59 pm

2. 

   Glad you liked it. You should see our new Blu-Ray test disc http://www.videouniversity.com/shop/blu-ray-test-dvd-kit

   Comment by admin — October 7, 2009 @ 6:28 pm

3. 

   I refer other camera assistants here for a clear explanation of the set up process of the monitor. Thank you for posting such a clear explanation.

   Comment by Stephen — November 24, 2009 @ 6:58 am

4. 

   thanks for this ot help me with my media studdies so much. =] thanks again

   Comment by lea — November 25, 2009 @ 3:08 am

5. 

   Reaaaly good explanation
   - Digital Film Student

   Comment by Lean — November 28, 2009 @ 8:13 am

6. 

   This is a good article minus any video
   hieroglyphics. But even after proper calibration
   for CRT or LCD the fact remains that many folk
   play DVDs in their default computer players
   which I have found make even good video look
   too dark. Is there a fine line between proper
   monitor calibration and the dvd computer player?Can I adjust for both worlds ?

   Comment by Vance — December 6, 2009 @ 8:28 am

7. 

   @ Vance
   I believe this has to do with colorspaces. Computers default to 0-255 colorspace and a TV expects a 16-235. If you have a high quality TV you may find a “Studio Color” or “PC Color” option. This should solve your problem if not:
   If your using Windows I’d recommend ffdshow tryouts and look at the Output and RGB Conversion. If your using Linux I recommend Mplayer with SMPlayer and read the Mplayer Man pages.

   Comment by Taco — January 13, 2010 @ 1:57 pm

8. 

   please tell us exact procedure to adjust pal monitors using color bars from camera

   Comment by swapnil — March 25, 2010 @ 11:24 pm

9. 

   Great information..!

   Under the displayed photos in this article it says
   “NTSC Color Bars”

   I am working in PAL, is there any difference or can I adjust my monitor with the above guidelines.

   Suzana

   Comment by Suzana — May 12, 2010 @ 5:02 am

10. 

    It would be great if this could be updated with the new smpte hd color bars. I am not quite sure what all the extra bars are for and if I need to worry about them.

    Comment by bk — May 28, 2010 @ 5:14 am

11. 

    Thanks for the great resource. I agree with #10-bk. As our TV station SLOWWWWLY transitions to HD acquisition, Im curious about the HD bars and set up.

    Comment by Dixon — August 6, 2010 @ 9:33 am

12. 

    Thanks. Your article helped me calibrate a new DLP projector which insisted in overdriving the picture.

    Comment by greet — August 25, 2010 @ 7:53 am

13. 

    Thanks Hal, using this settled a lot of arguments with students on the proper calibration of my display monitors in-studio.

    Comment by Jim Ross — February 20, 2011 @ 9:29 pm

14. 

    Very concise explanation! I have recommended that my students visit your site to get a different overview of the process.

    Comment by Tim Nelson — March 4, 2012 @ 10:21 am

RSS feed for comments on this post.

Leave a comment

Name (required)

Mail (will not be published) (required)

Website