Continuous vs. Sequential Color
Convert to Color Today! If you have a source
of color programming, you can convert your monochrome set to color. This page details the
changes that you need to make. I describe a continuous color system. These steps won't
work for field-sequential color. True, field-sequential color uses less bandwidth than
continuous color does. But there's a cost. With rapidly moving subjects, field sequential
color causes color ghosts. These ghosts are really "color flicker."
color also reduces frame rate or vertical definition by two-thirds. If your frame rate is only
12.5 fps, you'll certainly notice the flicker! These problems are why continuous
color is the preferred option for mechanical TV.
A Continuous Color Method
A continuous color project offers you several colorizing choices.
Start by deciding on a two-color, discrete three-color, or
derived three-color system. If naturalistic color isn't a goal, you have one
more option: Pseudocolor.
- Two-color systems
offer economical, simplified full-color pictures. If you have limited
space for additional circuitry, use a two-color circuit. Another reason
to consider two-color: Your power supply. Does it put out enough current
to power three LED drivers? Does it put out enough voltage to drive one or
more blue LEDs? Remember, blue LEDs take more voltage than red LEDs take.
A red and cyan system might avoid these current and voltage
problems. Learn more about two-color TV systems: Click
- Discrete three-color systems
offer full-color pictures that might include a broader
range of colors (gamut). Three-color circuits also offer more
controls. More controls is one advantage of increasing circuit
complexity by 33 percent. On the flip-side, more controls means
more adjustment time and more problems. Your choice.
- Derived three-color systems are
the happy medium between two-color and discrete three-color systems.
Additive primary colors all relate on the color wheel. The same is
true for electronic color that we use in television. Mix any two
primaries to form a complementary color. Invert the complementary
color, and you'll acquire the third primary color. That is, the
complement of the third color signal lies somewhere between the
other two color signals.
- Pseudocolor systems start with a monochrome signal and
interpolate colors. Pseudocolor systems accomplish this end by
assigning hue and saturation values to intensity values. Some medical
imaging and weather mapping systems use pseudocolors. In these types of
imaging, the number of discernable gray tones may be small. Yet in
pseudocolor images, an observer can detect color patterns where
corresponding gray patterns might be elusive.
- If you picked the pseudocolor option, please skip camera changes.
- Start with the camera. Duplicate your video preamplifier circuit
once for two-color TV. For three-color TV, add two more video
- Add color filters to the pickup devices: Red for the red circuit, and
so forth. With two-color TV, you'll achieve the best color
reproduction if you choose complementary colors. Some complementary
colors are probably better than others. For suggestions, see the table.
I've organized table color choices by how well they're likely to
perform. The top colors, orange and blue-cyan, are the basis for the
NTSC color model. These colors render flesh tones for all races
particularly well. Also, the human eye is more sensitive to orange
and blue-cyan than to their opposites. These opposites are magenta
2-Color TV with Complementary Colors
*Note: Most common choice, due to best flesh tone rendition.
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