What’s so special about these color bars?

You’ve seen these before. In fact you’ve probably seen them a thousand times before, or some variant of them. They’re referred to specifically as “SMPTE Color Bars” and they were developed by the Society of Motion Picture and Television Engineers to calibrate color TVs. They don’t have much use in today’s flat-panel, HD world but back when everything was analog, they were super-duper important. Now they’re just a geeky icon.

Here’s what a TV repairman would do (sorry for the sexist term, that’s what they were called.) The repairman would have three different pieces of colored glass or plastic that they would look through. Each color would block two of the colored phosphors of the TV, so they could see just the red, green, or blue parts of the image. If the TV’s tint was set right, the images would look like this:

Just Red

Just Green

Just Blue

The bars did other tricks, too. Using the grey/black bars at the bottom would allow brightness and contrast to be set, and looking at the edges of the bars would show issues in alignment and focus. In short, this was one useful image.

Today, with digital controls, these color bars don’t do as much as ones like this:

Color calibration isn’t as difficult as it used to be and at the same time with LCDs we don’t worry about focus and alignment. So it comes more down to fidelity and consistency, something like this image is much better off testing.

But somehow, it just doesn’t look as cool as an old-school SMPTE color bar, does it?

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 7,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.