An introduction to resolution and creating content for CRTs

When Creating content to be used with CRTs it is necessary to understand the limitations of their resolution

the video format used to send content to a CRT screen is PAL, standard definition with a resolution of 720 x 576 pixels

For content to be displayed on a single CRT, the above resolution should be used, and care should be taken to keep any text within what is called the “safe area”

The safe area is the space inside the PAL window that should contain all the important sections of content.

Due to the overscan of the screen, the area in the red may not show in full, so should be treated as a “bleed area” where background content can continue, but any text crossing over may get cut off.

When moving beyond a single CRT there are 2 options of how the videowall gets processed;

Option one is to use an original videowall processor from the same era of the CRTs, like the Media technologies Brick Processor. these units take a PAL signal in and can split this up to a 4×4 array.(multiple units can be combined to go beyond 4×4)

As the PAL signal has been stretched across 16 screens, the end result is an effective resolution of 180 x 144 pixels per screen. this will not be useful for detailed images or fine text, but some do like this lo-fi effect.

Option two is to send a full PAL resolution signal to each screen which contains a slice of the larger video content that makes up the videowall.  this can be done with scaler racks, playback servers or multiple media players.

This allows the highest resolution possible allowing fine details to be displayed.

In this example, we are making a 2 x 2 videowall with 4x CRT’s

this image is a 1920 x 1080 Full HD canvas, inside this we can fit 4x smaller windows that represent each CRT with a slightly reduced resolution from PAL to 675 x 540.

the black space on the right is unused.

We can then send each one of these sections to a CRT, keeping a high resolution along the way.

The useable pixel area in this setup is 1350 x 1080.

Here we have a 4 x 4 videowall using 16x CRTs

The image is 3840 x 2160 4K UHD canvas, inside this, we can fit 16 of the same size windows as above (675 x 540) 

the usable pixel area of this setup is 2700 x 2160.

By using modern techniques and equipment we can bring the demand for high-resolution content to CRTs that are over 22 years old!