Hue, Saturation, And Lightness Palette; Selective-Color Palette; About Rgb And Cmy - Minolta Dimage Scan Software Manual

Hue, saturation, and lightness palette

This palette adjusts the image in reference to the HSB color model. These controls
can be used to manipulate the color image rather than producing a realistic
representation.
The HSB color model defines color based upon human perception rather than
photographic processes. Hue refers to each separate color in the model. Saturation is
how vivid each colors is. Lightness describes how bright or dark a color is in the color
space.
The hue control is not a color balancing tool. It is a creative tool. When changing hue
in the palette, each color is assigned a new hue depending on the degree of rotation
through the color space. For example, a very simple color space could have three
colors: red, green, and blue. I have a red barn next to a green tree with a blue sky.
Now I rotate the image in the color space; the colors are reassigned a new hue based
on the position - the barn is green, the tree is blue, and the sky is red. The HSB color
space is similar, but with many more hues; see the color example on page 75.
Unlike the brightness control in the brightness, contrast, color balance palette, the
lightness control does not change the apparent density of the colors equally. For
example, with an extreme increase in lightness, blue will not appear as light as yellow.
Click the hue, saturation, and lightness button to
open the palette.
Drag the hue, saturation, or lightness slider, or
enter specific values in the corresponding text box
to make corrections; changes will be reflected in
the display image. Dragging each slider to the
right or inputting a positive number in the text box
increases the saturation, and lightness. The hue
slider rotates the colors in the image through the
color space; the maximum position to the right
(180°) is the same as the maximum position to the
left (–180°). Click the reset button to cancel any
changes.
Two color samples are displayed at the bottom of the palette. The top bar indicates the
color space of the original image. The bottom bar displays the relative changes to the
color space.
Clicking the auto-setting button adjusts the saturation automatically without affecting
the hue or lightness. Click the reset button to cancel any changes.
56 A
DVANCED IMAGE PROCESSING
Original color space
New color space

Selective-color palette

Selective-color correction is an advanced technique to refine the colors in the image.
A cyan, magenta, yellow, and black channel can be used to adjust the six separate
color groups in the image: red, green, blue, cyan, magenta, and yellow. The black-
level slider controls the brightness of the selected color group.This type of correction
is effective in changing a specific color without influencing any of the other colors in
the image. For example, if the sky looks purplish instead of blue, magenta can be
reduced in the blue color group. See page 75 for a selective-color example.
Click the selective-color button to open
the palette.
Select the color group to be corrected from the drop-down
menu at the top of the window.
Drag a slider or enter a value in a text box to adjust the
selected color group. More than one slider can be used to
adjust the selected color. Changes will be reflected in the
display image. Click the reset button to cancel any
changes.

About RGB and CMY

The RGB color model is an additive process that uses the primary colors of light: red,
green, and blue. An additive color system mixes the three colors to recreate the entire
spectrum of light. If all three colors are mixed, white light is produced. Television sets
and computer monitors use RGB to create images.
The CMY color model is a subtractive process that uses the secondary colors: cyan,
magenta, and yellow. A subtractive color system recreates color with pigments and
dyes to absorb unwanted color. If all three colors are mixed, black is produced. Film-
based photography is a subtractive process. Printing technology is also a subtractive
process, but, unlike photographic systems, it requires a black channel (K). Because of
the imperfections of printing inks, cyan, magenta, and yellow cannot produce a true
black when mixed, printers use what is called a four-color process (CMYK) to
reproduce images.
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