Photoshop Tutorials - RGB Color Model
RGB Color Model
RGB color model describes the emitted colors. Basic components of the model are three colors of the rays - red, green, blue. During the image sensing these three colors are sensed by the human eye. Other colors are just the mixes of three basic colors in certain proportions. Every constituent can change its value from 0 to 255, so you get access to 16 millions of colors.
When two rays are blended (combined), the result is lighter then any of the components. Such colors are additive colors. This model is used in all monitors, projectors and other devices that emit or filter the light, including TV sets, film projector and colored floodlights. Web designers in their work are oriented at computer monitor as an output device, so we will mostly learn to work with images in RGB color model.
I would like to remind you that RGB is three-channel and 24-bit (color of one pixel is determined by 24 bits - one byte per channel) model
The color field is easy to display as a colored cube. The values of three basic color channels are situated along the datum lines. Each of them can have the value from zero (no light) to maximum (maximum brightness). The sides of the cube contain all colors of the model. In the point of origin the values of all three channels are equal to zero (black color); in the outermost of every datum line the maximum brightness forms the white color. Along the line that connects these two points there is a gradient of the grey color, grayscale.
Three of the cube tops have the pure initial colors while other three depict the dual mixes of the initial colors. In regular RGB mode, every color channel and grayscale have 256 gradations (hues).
The image created in RGB color model can be saved in any graphical format supported by Photoshop, except GIF format. The drawback of RGB mode is that you cannot print out all of the colors. You can avoid the color loss editing the image in CMYK mode.