Graphics Programs Reference
In-Depth Information
storing Color in Channels
You might be surprised to learn that camera sensors do not directly record unique
colors. For example, there is no orange sensor. Orange is recorded as a combination
of red, green, and blue light intensities represented as (255,168,0) in 8-bit color. The
human eye has three types of cones mapping roughly to red, green, and blue wave-
lengths, so there is a strong correlation between how we record additive color and
how we see.
In Photoshop, color is stored in channels. Channels are nothing other than
grayscale images. In RGB color there are three channels, one for each primary.
So an RGB file has three grayscale pictures in one file. Ponder the paradox—
there is literally no color in the digital representation of color. Figure 3.9 shows
an RGB image created entirely from its three constituent grayscale channels.
FIGURe 3.9
Red (left), Green (middle), and Blue (right) channels
Each channel in the Photoshop file is sent to corresponding red, green, and
blue subpixels for display on your monitor. When this light enters your eyes, three
types of cone structures pick up varying intensities of red, green, and blue light
and turn this information into a color picture in your mind (see Figure 3.10).
FIGURe 3.10
Color photo created from RGB channels
