Chapter 5: Working with Colors and Materials
104
To describe how color is produced or perceived, we use color
models. Computer monitors display colors by producing varying
amounts of red, green, and blue light—the RGB color model. Human
eyes perceive color by its hue, saturation, and lightness levels—the
HSL color model. With Paint Shop Pro you can select colors using
either the RGB or HSL color model. You can also output images
using the CMYK (Cyan, Magenta, Yellow, Black) model, which is
used for high-end printing applications.
RGB Model
All colors on your computer screen are created by mixing red, green,
and blue light in varying proportions and intensities. Adding all the
colors together creates white.
Each primary color (red, green, and blue) is assigned a value from 0
(none of the color present) to 255 (the color at full strength). For
example, pure red is produced by combining a red value of 255, a
green value of 0, and a blue value of 0. Yellow is a combination of a
red value of 255, a green value of 255, and a blue value of 0. Setting
all three values to 255 produces white; setting all three values to 0
produces black. When all three colors are set to the same value (such
as 120, 120, 120), the result is grey.
HSL Model
The HSL model is based on how the human eye perceives color
using the characteristics of hue, saturation, and lightness. Each
characteristic is assigned a value from 0 to 255. The three
characteristics are described as follows:
Hue The color reflected from an object, such as red, yellow, or
orange. Each hue value is assigned based on its position on the color
wheel. On the Jasc Color Picker’s color wheel, colors are assigned
counter-clockwise from the top. Red is at the top (value 0) and as
you move around the wheel the colors go through orange, yellow,
green, blue, purple, and back to red.
Saturation The purity or vividness of the color. Saturation represents
the amount of grey in the color, from 0 (entirely grey) to 255 (fully
saturated color).
Lightness The perceived amount or intensity of light in the color.
Lightness ranges from 0 (no light, or black) to 255 (total lightness,
or white). At 50 percent lightness, or a value of 128, a color is
considered pure. For example, pure red has a hue of 255, a saturation
of 255 (100 percent) and a lightness of 128 (50 percent). For pure
blue, the hue is 170, saturation is 255 and lightness is 128.
Selecting the color model
RGB is the default color model. To
change your color model
preference, see “Display and
Caching Preferences” on
page 395.
Paint Shop Pro uses your preferred
color model (RGB or HSL)
whenever color values are
displayed, such as with the
Dropper tool. When you select
colors from the Jasc Color Picker,
you are able to enter RGB or HSL
values regardless of your
preference setting.
The color model used to display
color values on-screen has no
effect on how colors are printed.
Choose a color model preference
that is easier for you to use.