How to use color bars and test patterns

Why color bars still matter

Color bars look like a relic from old television, but every video crew still uses them. They are a known, fixed reference. If the bars look right at the far end of your signal chain, the picture is getting there intact. If they do not, you know something in the chain is changing your image before a single camera is involved.

That makes test patterns the fastest way to answer questions like:

• Is this monitor set up correctly?
• Is the capture card or converter changing my colours or levels?
• Is the projector cropping the edges of the image?
• Is this signal actually reaching the stream, the record deck or the venue screens?
• Is my audio getting through too?

Free online test patterns

You do not need a signal generator to use test patterns. Our free color bars and test patterns tool runs in any browser. Open it on a laptop, go fullscreen and send that laptop’s output down the chain you want to test.

It includes:

• SMPTE color bars
• Grayscale steps
• Grid and crosshatch
• PLUGE
• A 1kHz reference tone you can switch on and off

Your choices are saved in the page URL, so you can bookmark a setup and open it straight into the right pattern next time. Add hideControls=true to the URL to keep the controls hidden on an output display.

What each test pattern is for

SMPTE color bars

The classic. Seven vertical bars across the top (white, yellow, cyan, green, magenta, red, blue), with smaller reference patches underneath.

Use them to:

• Check colour and saturation. On a correctly set up monitor, each bar is a clean, even block of colour with no bleeding between bars.
• Spot swapped or missing channels. If the colours are in the wrong order or a bar is missing, a cable, converter or setting is wrong somewhere.
• Identify a source. On a router or multiviewer, bars tell you instantly that this input is live and coming from a test source, not a camera.

PLUGE

PLUGE stands for Picture Line-Up Generation Equipment. It shows a row of near-black bars, some slightly darker than black and some slightly lighter.

Use it to set a monitor’s brightness (black level). Turn brightness up until you can see all the bars, then bring it down until the darkest bar disappears into the background while the slightly lighter bar stays just visible. Now your blacks are black, but shadow detail is not crushed.

Grayscale

A set of steps from black to white. Use it to check contrast and to make sure every step is distinct. If neighbouring steps at the top merge into one white block, highlights are clipping. If steps at the bottom merge, shadows are crushed. A grayscale with a colour tint means the monitor’s white balance is off.

Grid and crosshatch

A grid of evenly spaced lines with circles and a crosshair in the middle. Use it for geometry and alignment:

• Check a projector is square on the screen, with straight lines and round circles.
• Confirm the image is centred and not cropped by overscan.
• Line up multiple screens or an LED wall so lines continue cleanly across the joins.

1kHz tone

Bars and tone go together. A steady 1kHz sine tone lets you check the audio path end to end at the same time as the picture: that it arrives, that it comes out of the correct channel, and that levels match across devices.

A quick line-up routine

Here is a simple routine for any show:

1. Send bars and tone from the source end. Open the test pattern tool on the computer that will feed your switcher or stream.
2. Check every monitor in the chain. Confirm colours on the SMPTE bars, set brightness with PLUGE and contrast with grayscale.
3. Check projectors and LED walls. Use the grid to check focus, keystone and cropping.
4. Check audio. Turn on the tone and confirm it reaches the mixer, the record and the stream at the expected level.
5. Send it to the stream. Run bars on a private or unlisted stream to confirm the whole path works before the real thing.

Test patterns inside your show

If you already run graphics with H2R Graphics, the Pro Test Pattern graphic puts bars and tone right in your rundown. Choose from colour bars, a grid with screen dimensions, or EBU 75% bars, with a built-in reference tone. Fire it from the rundown or a Stream Deck before doors open, then take it off when you go live.

More free broadcast tools

• Color fill for solid colours, green screen and blue screen backgrounds.
• Safe area overlay for title safe and action safe guides.
• On air light to turn any screen into a tally or on air sign.
• Countdown timer for starting soon screens.

Open the test pattern tool and line up your next show in minutes.