Graphics Programs Reference
In-Depth Information
The RGB color model
The RGB (Red, Green, Blue) color model is an additive model in which red, green, and
blue are combined in various ways to create other colors.
1
Choose File > Open, and navigate to the ps06lessons folder. Open the i le named
ps06rgb.psd. An image with red, green, and blue circles appears. Try to imagine the three
color circles as light beams from three l ashlights with red, green, and blue colored gels.
Red, green, blue.
2
Select the Move tool ( ), and then check the Auto-Select checkbox in the Options
bar. By checking Auto-Select Layer, you can automatically activate a layer by selecting
pixel information on that layer. One at a time, click and drag the red, green, and blue
circles around on the image.
Notice that white light is generated where the three colors intersect.
3
Now, turn of the visibility of the layers by selecting the Visibility icon ( ) to the left
of each layer name, with the exception of the black layer. It is just like turning of a
l ashlight; when there is no light, there is no color.
4
Choose File > Close. Choose to not save changes.
The CMYK color model
CMYK (Cyan, Magenta, Yellow, and Black [or Key]—black was once referred to as the
Key
color) is a subtractive color model, meaning that as ink is applied to a piece of paper,
these colors absorb light. This color model is based on mixing CMYK pigments to create
other colors.
Ideally, by combining CMY inks together, the color black should result. In reality, the
combination of those three pigments creates a dark, muddy color, and so black is added to
create a panel with true blacks. CMYK works through light absorption. The colors that
are seen are the portion of visible light that is rel ected, not absorbed, by the objects on
which the light falls.
