CHAPTER 7. COLORS 73
Hue refers to angle on acolor wheel, where 0 (or 360) is red, 120 is green,
and 240 is blue.
Saturation refers to color vs gray scale. 0% is gray, like an old black-and-
white television. 100% is full color.
Lightness refers to tint and shade, as though you were adding paint to
the color, white (tint) to lighten it, or black (shade) to darken it. 0%
means completely black (maximum shade). 100% means completely white
(maximum tint). 50% is natural color, without shade or tint.
Tint means to add white. Tone means to add gray (equal parts of white
and black), which is accomplished by way of the saturation control. Shade
means to add black.
7.2 The RGB Additive Model
Web colors are based on an additive model, using Red, Green, and Blue
light as the nominal components. (I say “nominal” because the green is
really more of a lime color.) The more colors you put in, the lighter the
color becomes.
Regular painting is based on a subtractive model. The more colors you put
in, the muddier the paint becomes.
Exam Question 113(p.343): In rgb, what does the r stand for?
Required Answer:red
Exam Question 114(p.343): In rgb, what does the g stand for?
Required Answer:green
Exam Question 115(p.343): In rgb, what does the b stand for?
Required Answer:blue
7.3 Layers and Transparency
Subtitles on television or movies are often provided for alternate languages
or for hearing impaired viewers. Often these subtitles are overlaid right onto
the movie itself.
HTML allows for layers of material. You can have a background image
with content that overlays the image. You can have a picture that has