Spectrac: Color for a
Monochrome World

Belt System Color. From Canada, with love! (and technical genius.) Fred Topping's Spectrac Converter used his proprietary scanning belt to reproduce color television pictures. But Spectrac achieved something even more fascinating: It reproduced dazzling color pictures on a black-and-white television receiver. And those pictures attracted a crowd at the 1971 Summer Consumer Electronics Show in Chicago. [Ben., 45]

Spectrac offered a deal. That year, color TVs were expensive. But everybody wanted one! If you couldn't pay the freight, but could turn a screwdriver, Spectrac offered a deal: For $100, Spectrac would ship you a converter kit. You'd assemble it. Afterward, the monochrome TV you already had could start pulling in those fabulous color shows! (Of course, the broadcasts had to be in color in the first place.) [Ben., 45]

Belt. The Spectrac TV viewer watched the monochrome picture through a moving belt. The belt traveled horizontally across the TV screen. Running across the belt in a gentle slant to the vertical were opaque black stripes: Hundreds of stripes. From the viewer's perspective, the front of the belt moved from right to left. The back of the belt moved from left to right. (The viewer looked through both front and back.)

Invisible. At a normal viewing distance, the stripes were invisible. Each stripe was only 0.022 inch wide. Between stripes, the belt was clear. [Ben., 46], [Top., 7, Col. 3]

Color filter. Between layers of the belt was a stationary filter. The filter bore stationary, slanted, color stripes. The colors were transparent. Each stripe was 0.022 inch wide, matching the width of each disc stripe. The reason for the size match was this: Belt movement exposed a red stripe or a cyan stripe. The monochrome picture played behind these stripe filters. [Ben., 46] (Incidentally, cyan is a mixture of the primary colors blue and green.)

Drawing of Spectrac belt from U.S. patent. Highlights: 12—Spaced rollers for belt drive; 14—Idler rollers; 16—2-Color stripe filter; 17—Roller drive motor; 19—Opaque stripe; 21—Transparent stripe. [Top., 1, Fig. 1; 7, Col. 4]

Stripes on the belt. Stripes on the front of the belt slanted left, in parallel with the color stripes. [Top., 7, Col. 4] On the back of the belt, the stripes slanted right. From the viewing position, the belt moved from right to left. [Ben., 46]

Color diamonds. Result: The belt alternately exposed or obscured portions of color stripes. Each exposed portion was the shape of a tiny diamond. The diamonds were either red or cyan. [Ben., 45]

Red or Cyan Screen. Due to belt travel, “diamonds” swept down the screen. After the screen became entirely red, cyan would begin to paint over the screen. Soon the screen would be entirely cyan. And then red would creep over the cyan again. [Ben., 46-47]

Top view, Belt from patent. 10—Belt; 20—Photocell pickup; 22—Exciter lamp. (Other callouts same as on Fig. 1, above.) [Top., 1, Fig. 2; 7, Col. 4; 8, Col, 6]

• Adapters for CRT. The kit included “standard” CRT connectors, allowing the kit to just plug into a TV. [Ben., 45]

• Color fringes: None. [Ben., 47] Spectrac used a one-gun picture tube. Convergence (between guns) simply couldn't go out of whack.

• Controls. Spectrac adapted an NTSC chroma demodulator board from a Canadian TV manufacturer. The color controls were the same as for other NTSC color sets: HUE and INTENSITY (SATURATION). [Ben., 45]

Frame Flicker Rate
Spectrac	30 Hz
NTSC	30 Hz
Col_R_Tel	10 Hz

Source: Author

• Cost. $100, vs. $500 for a color TV at that time. (Assumes that you'd mount Spectrac on the black-and-white set you already had.) [Ben., 47], [Kar., 3]

• Flicker. Slight or none. [Ben., 47]

• Solid-state. No tubes to burn out. [Ben., 47]

• Wear: No strain on motor. The belt allowed the belt motor to poke along at 1.3 rpm. [Ben., 46] (In one inch of travel, the belt colored (1/0.002), or 45 video fields.)

• Assembly. Spectrac required assembly. [Ben., 45]

• Colors: Two primaries instead of three. The most important colors, flesh tones, were accurate. But other colors would shift, or render in gray. [Ben., 47] (Examples: Gray instead of green. Pink instead of yellow. Red-orange instead of orange. Grayish cyan instead of magenta or blue.) [Cin.]

• Detail. The black stripe filter halved the horizontal resolution. The converter only added color to one field per frame, dropping the second field. The color stripes were also dense. [Ben., 47] Such was the cost of the low flicker rate.

• NTSC. Spectrac only worked on NTSC sets. (Source: Author)

• Size. Somewhat larger than the TV set. [Ben., photo, 45]

• Screen size. A 20-inch system was the largest practical TV screen size. [Ben., 45]

• View only in dark. Reduced picture brightness 90% [Ben., 47] (vs. 50% for shadow-mask color tube).

Demise of Spectrac. After CES 1971, the progress on the Spectrac project depended on the availability of venture capital: Specifically, a Canadian government loan. The loan was necessary so that Spectrac Ltd. could finish research and start mass production and marketing. But the government denied the loan and a subsequent appeal. Without funds, Spectrac's parent company Topping Electronics returned to its R&D business. [Kar., 2]

Still in business. Topping Electronics still maintains offices in Scarborough, Ontario. The company makes traffic control equipment. [T.E. pg.] Frederick V. Topping retired from his Topping Electronics in 1989. Afterward, Topping Electronics became a division of InspecTech Analygas Group Inc. Topping died in September, 1999. [Ill.]

Rival product. How much competition did Spectrac face? The closest product to a “Spectrac competitor” was the 1965 Scope converter. (Apparently, neither Scope nor Spectrac went into broad distribution. They may have been competitive ideas, but they weren't marketing opponents.)

Scope's Two-color filter. Like Spectrac, Scope suspended a two-color stripe filter over the TV screen. In Scope's rendition, the stripes were orange and teal. (Teal is slightly bluer than cyan.) Instead of a traveling belt to block one or the other color, Scope employed a moving screen overlay. [Lac., 33]

The Scope overlay bore vertical, opaque black stripes. The black stripes alternated with transparent stripes. A linear vibrator positioned the black stripes to obscure either the orange or the teal filter stripes: Very similar to Spectrac, except that Scope's linear vibrator pulsed rapidly. (But Scope's overlay didn't move far: In both ways, unlike the leisurely progression and long travel of the Spectrac stripe belt.) [Lac., 33]

The TV vertical signal fed through a power amplifier that drove the vibrator. The drive electronics must have been close to what Spectrac used. [Lac., 33]

NRI Connection. In 1965, NRI Schools was producing the Scope converter. NRI announced that it planned to market the Scope system to TV manufacturers. The goal was a $200, two-color TV. The Scope converter unit by itself would market for $109. [Lac., 33]

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