Test Card - Decline

Decline

Formerly a common sight, test cards are now only rarely seen outside of television studios, post-production, and distribution facilities. In particular, they are no longer intended to assist viewers in calibration of television sets. Several things have led to their demise for this purpose:

• Modern microcontroller-controlled analogue televisions rarely if ever need adjustment, so test cards are much less important than previously. Likewise, modern cameras and camcorders seldom need adjustment for technical accuracy, though they are often adjusted to compensate for scene light levels, and for various artistic effects.
• Use of digital interconnect standards, such as CCIR 601 and SMPTE 292M, which operate without the non-linearities and other issues inherent to analogue broadcasting, do not introduce colour shifts or brightness changes; thus the requirement to detect and compensate for them using this reference signal has been virtually eliminated. (Compare with the obsolescence of stroboscopes as used to adjust the speed of record players). On the other hand, digital test signal generators do include test signals which are intended to stress the digital interface, and many sophisticated generators allow the insertion of jitter, bit errors, and other pathological conditions that can cause a digital interface to fail.
• Likewise, use of digital broadcasting standards such as the DVB and ATSC eliminates the issues introduced by modulation and demodulation of analogue signals.
• Test cards including large circles were used to confirm the linearity of the set's deflection systems. As solid-state components replaced vacuum tubes in receiver deflection circuits, linearity adjustments were less frequently required (few newer sets have user-adjustable "VERT SIZE" and "VERT LIN" controls, for example). In LCD and other deflectionless displays, the linearity is a function of the display panel's manufacturing quality; for the display to work, the tolerances will already be far tighter than human perception.
• In developed countries such as the United States and the United Kingdom, the financial imperatives of commercial television broadcasting mean that air-time is now typically filled with programmes and commercials (such as infomercials) 24 hours a day, and non-commercial broadcasters have to match this.

Test cards and other semi-static programming and their use around the world today:

• In North America, most test cards such as the famous Indian Head test card of the 1950s and 1960s have long been relegated to history. The SMPTE color bars occasionally turn up, but with most North American broadcasters now following a 24-hour schedule, these too have become a rare sight. Many Canadian Broadcasting Corporation stations broadcast a modified form of the SMPTE bars (with an additional modulated ramp at the top and a CBC logo animation in place of the Q block) late at night until late 2006, when the network moved to 24-hour broadcasting.
• When there are in fact no standard programmes being broadcast on the channels that do not have 24-hour programming, other, more informative features such as educational shows, e.g. the BBC Learning Zone, and teletext-type programmes such as Pages from Ceefax, ITV Nightscreen and 4-Tel On View are often broadcast, the latter type acting as the better test-card substitute as they just roll continuously.
• Australian national broadcaster SBS airs Weatherwatch, a weather map accompanied by music from albums sold by SBS and a ticker at the bottom of the screen during the early hours of the morning.
• Australian community broadcaster Channel 31 in Melbourne previously aired Fishcam, the output of a videocamera aimed at a fish tank.
• Some Philippine cable networks replace test cards with an advertisement showing the product, "a reason to go to sleep" and the time when the station will sign on.
• In Malaysia it was officially inaugurated to grand opening on 1 June 2011 by the TV Alhijrah it was officially instead of showing test cards, television channels usually air music theme "歡顏" with vocalist to singers by Nikita Willy. while showing their Astro logo at the same time.
• In Singapore, since 2005, instead of showing test cards, television channels usually air radio channels while showing their station ident at the same time.
• In Thailand, all private and semi-private channels that does not have a 24-hour schedule broadcasts teleshopping programs in the off hours, and public channels broadcasts rerun programs. Today, 5 out of 6 television channels does not have a 24-hour schedule, only TV3 has a full 24-hour schedule. Test cards are no longer broadcast in Thailand since January 2011, with Thai PBS being the last channel to broadcast test cards.

On television networks and stations in most of the Third World countries, test cards are still seen because most television networks and stations in those countries do not have 24-hour programming.

Use of test patterns and test cards is still common within television production facilities. Many of these still have analogue infrastructure, and currently as of March 2006 analogue transmissions are still found worldwide (though the United States is currently scheduled to require broadcasters to switch off the NTSC service in 2009—NTSC may still be a viable transmission means for cable television for several more years). Many artistic settings are still made by using test cards or test patterns in conjunction with devices like waveform monitors and vectorscopes (most modern waveform monitors include vectorscope capability), and while digital transmission eliminates many of the "analogue" effects associated with analogue television, digital broadcasting has its own set of issues.