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Comments (15) Posted 01.21.09 | PERMALINK | PRINT

Steven Heller

That Pesky Television Test Pattern


Indian head test pattern

What came first, television or the television test pattern? By all accounts, the once ubiquitous, static bullseye that appeared on kinescopes and cathode ray tubes from the 40s through the 70s before stations began airing their scheduled programs (or when malfunctions occured) may not have preceeded the actual invention of television, which surprisingly began during the 1880s, but it was the first real transmission that was seen on TV. Although the earliest dimensional image to appear on the screen in the mid-thirties on NBC’s experimental station W2XBS was a rubberized model of Felix the Cat (the only object that would not melt under intensely hot studio lights), the test pattern was the most consistently broadcast image since the early twenties.

NBC test pattern

The origin of the pattern is a story of form following function. Aesthetics were irrelevant to the primary purpose, and the technical draftsmen who anonymously designed it could have never predicted that decades later it would become a nostalgic icon. The intent was to enable engineers, who in the so-called “pre-television” days were the only persons to actually receive broadcasts, to calibrate the extremely small, very crude black and white scans that became the TV picture. While the circular target may seem odd given the rectangular shape of even the earliest screens, in fact, the initial test patterns conformed to the circular shape of an oscilloscope that showed engineers the electrical equivalent of an image in the form of a wave. But there was an even more deliberate rationale. 

In the twenties test patterns (or test charts as they were refered then) were more or less varied, but in the late thirties, when a few hundred receivers became commercially available, a standard was embraced by broadcasters. The chart was designed to both check transmitter performance from the studio to the antenna and allow the audience to determine the degree of performance of their individual receivers. In addition to the advantage of being a static signpost, of sorts, the chart revealled geometrical defects, horizontal and vertical degrees of picture resolution, and a range of shadding gradations.

The archetypical chart used by NBC/RCA, which in the thirties had merged to form the first television “network,” consisted of an outer circle that had a diameter equal to four-thirds the diameter of the inner circle; the former touched the sides of the screen and the latter was cut off on top and bottom. This conformed to the standard aspect ratio of 4:3. If the picture was too narrow (less than the aspect ratio), the circles took on an eliptical shape, with the major axis of the ellipses in the vertical direction; the converse was true if the picture was not high enough. The chart was, therefore, a diagnostic device to determine whether the transmitter scanning was too wide or narrow, too great or too little. The large circles had another important use. The scanning of the beams at transmitter and receiver had to move at a perfectly uniform rate or else the image would be expanded or condensed. If the circles were egg-shaped then the scanning was not uniform. The perceived defects could then be fixed by precision controls on the transmitter. Presumably, home receivers required only a one time setting upon installation, but invariably dials would shift so the test chart would aid the viewer in making the necessary adjustments. 

KMOX TV test pattern


The interior of the pattern was divided into sections. The innermost, shaded circles, consisted of three concentric circular areas of differing density: the central area being black; the next an intermediate gray tone and the outer, was white. These were used to measure and set the contrast controls either at the transmitter or receiver. If the contrast control was set too high, the two inner areas turned to black, eliminating any degree of shading. Conversely, if the constrast was low, the picture becomes very flat or gray. 

The bars that shot out from the bullseye in four directions, called “definition wedges,” consisted of vertical and horizontal black and white lines, arranged to increase in width as they moved out from the center. The horizontal lines were used to measure vertical resolution, and the vertical lines measured the horizontal, the measurments were based on scan lines (a maxiumum then of 350 lines) of the screen. Like registration marks, the wedges highlighted faulty resolution and electrical focus that could be fixed at the point of origin. If the home users had read the TV manual they would know how to use the test chart, which in the early days of television appeared more frequently than the live programming. But by the fifties the test pattern was shown in the early morning or very late at night and most users randomly fiddled with the knobs and antenna, ignoring its functional benefits.

By the early fifties every TV station in America used a version of the same basic test chart until twenty-four hour broadcasting made it obsolete in the seventies. But one question remains unanswered. What about the most ubiquitious of all the pattern designs — the one with the picture of the indian? Where did it originate? Everyone recalls it, yet no one knows why the indian was used.


For a related article, please see this previouse Design Observer post, by Dmitri Siegel: The Mysterious Disappearance of Carol Hersee
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Comments (15)   |   JUMP TO MOST RECENT >>

Wow, I remember seeing those. Also remember the sometimes humorous "Please Stand By… We Are Experiencing Technical Difficulties" screens. Remember one in St. Louis that was an illustration of a guy with headphones on at a control panel, holding a bunch of unplugged wires. And he had three arms. It was for the local PBS channel. Funny stuff!!!

VR/
Joe Moran
07.27.09 at 01:26

You get into a grey area (heh) by lumping "test patterns" into one category...plain ol' analog NTSC television has had a lot of them, for special purposes. There are the test pattern/ID/slides that they put up at the edges of the broadcast day...more than anything, they were to serve as a legal ID first, and secondarily make sure that the transmitter, as it came up and stabilized (tubes warming up, remember), was in the ballpark of doing the right thing.

TV registration charts, with a grid pattern along with concentric circles, ensured the multiple tubes of a color camera or camera in a "film chain"--the assembly where slides and motion picture film became a TV signal-- were aligned with each other (once a lengthy, manual process), and the 'chip chart' --a series of greyscale squares -- made sure the tubes of the color camera were putting out matching levels so that a proportioned grey signal--not too red, too blue, or too contrasty--was put out.

You could accidentally see any of these on the air--depending on what piece of equipment was being tested. But most often, the camera-setup patterns were only seen by engineers within the station's facility. If it went on the air, it tended to have the station's call letters--legal IDs used to be important.

As Chuck Pharis elaborates, the Indian Head test pattern was created by a specialized piece of RCA gear (the "TK-1C Monoscope Camera"), and thus found its way into many TV stations. (Chuck is a legendary TV equipment collector, and a bit of a capitalist--he's selling reproductions of the original test pattern art.) The Wiki-P entry is pretty complete on its origins...the "why" is they needed a detailed, standardized line drawing, and they had this one.

Yes, I hang around a lot of TV geezers.
J.C.Burns
07.27.09 at 03:38

It was common when TV first came out. You used to see these all the time. I think it also keeps broadcasters in screen safe areas

Nicolette
http://www.furnitureanddesignideas.com/
Nicolette
07.27.09 at 05:35

When my wife and I talk about TV in our respective households growing up, both of us, independently (me in New York, she in Indiana) experienced turning on the TV and finding "the indian" on.
Richard
07.28.09 at 09:01

Being a child of the 80s I only remember the color bars. They have a set for HD now too.

http://en.wikipedia.org/wiki/File:SMPTE_Color_Bars.svg
Nick
07.28.09 at 10:37

I'm old enough to remember B&W test patterns, but don't remember them well enough to say "I saw *that* one!"

Those interested in test patterns in the UK might wish to visit http://www.testcardcircle.org.uk/
DMcCunney
07.28.09 at 11:37

The game Fallout 3 uses this static image in a really beautiful way for the load screen at the beginning of each game and during certain load times throughout. very cool.

http://image.com.com/gamespot/images/2007/news/06/05/fallout3_screen003.jpg
Ryan Thompson
07.29.09 at 12:28

These oddly mesmerizing test patterns were followed by the morning farm report in my suburban childhood (creating a kind of kinship with the not so distant reaches of agriculture - then thriving in San Diego's Mission Valley). The farm report pictured a single rooster with the sun rising behind it while news of the day's favorable or unfavorable agricultural conditions were narrated in somber tones by an off-screen reporter. I must have been an early riser. Thanks for the trip down memory lane.
Vickie Pynchon
08.11.09 at 11:18

Besides the "Indian head" - which was "lined" rather than gradated due to the fact that monoscopes could only reproduce black and white, period - there was another "lined" pattern, which was based loosely on the NBC test pattern shown here. Test patterns were usually presented in the following ways: on boards or cards (hence the British "test card" terminology), 35mm slides (as the case from the mid-1960's onwards with color patterns that were adaptations of the NBC pattern), light boxes (with 8" x 10" transparencies), telops, or (in the case of the Indian head) monoscopes. It was also not unheard of for stations to have such patterns at both their studios and their transmitting facilities. Sometimes there were slight differences from the two sources.
W.B.
08.23.09 at 12:23

While for station i d visual, came upon your site.
I work in televison broadcasting, have so since 1975. As a kid growing in chicago, Il I saw those test patterns.

I work KMOV ch 4 known in it's CBS days as KWK-TV and then KMOX-TV. One of my prizes is a kinescope of the KMOX-TV test.

I got into the business because I fell under it's spell, finally, I have a picture of WCIU-TV Channel 26, Chicago's first UHF station. Anyway nice site, (as we leave the air, we invite you to join at this same time again, please standby for WCRW, WSBC sharing this frequency, the time as we leave the 4:35 p.m
gene a stamps
10.16.09 at 05:36

An interesting article about the history of test patterns. As a master control operator at KDOC in Anaheim, CA in the mid 90's we used the SMPTE color bars to calibrate the over-the-air transmitter output before officially signing on at 6AM every weekday morning. They were also (and still are) recorded at the start of program tapes to set the levels before it went to air.

During the US digital TV transition on June 12, 2009 (and February 17 before that), several stations made the final analog sign-off into a big production, with a formal legal station ID, a flashback video of events in that channel's history, a video of "The Star Spangled Banner", then the Indian Head test pattern. It was probably done for nostalgia's sake, but the transition was indeed an historic event in broadcasting history and that was not lost on those stations.

I have a playlist of some of those test pattern analog sendoffs on my YouTube page:
http://www.youtube.com/user/richartrod#grid/user/D364DB45D14B329C

Test patterns are still used in-studio at TV stations, but they are obviously now reformatted for widescreen, 1080-pixel high definition.
Rich Rodriguez
12.08.09 at 03:40

Absolutely fabulous page. Thanks to all and especially for the links.
LarryL
03.06.10 at 07:15

HAHAHAAA
Thanks for the memories! I vaguely remember the Indian, and definitely remember the last one!! I hated those things as a kid they seemed to be on FOREVER before Saturday AM cartoons!!! Then in the early 80s as a college freshman, I got a job at the local tv station, and had to line up the old cameras on them, then the engineer fired up the color bars, and we'd sign on, and yes the Farm & Home report!!! I knew as a kid, after he'd finally shut up...CARTOONS (or Bozo, Romper Room or Capt.Kangeroo during the week).
Dale Mc
05.27.10 at 10:00

When CBC's Bilingual station CBFT came on the air in Montreal in 1952, the event went off without a hitch. When CBLT came on the air in Toronto two days later, someone put the test slide into the projector backwards. They never revealled the name of the culprit...
Geolee
06.07.10 at 01:52

I'm confused as well as some of my friends. We're from Canada and almost all of us remember the Indian Head being in the centre and being much bigger. Any thoughts?
r baird
01.18.11 at 01:17



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Steven Heller is the co-chair (with Lita Talarico) of the School of Visual Arts MFA Design / Designer as Author + Entrepreneur program and the SVA Masters Workshop in Rome. He writes the Visuals column for the New York Times Book Review, a weekly column for The Atlantic online and The Daily Heller.

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