Every Adobe Photoshop image has one or more channels for storing information regarding the color elements of the image. An image can be have upto 56 channels. The number of default color channels in an image depends on its color mode. For example, a CMYK image has at least 4 channnels, one each for Cyan, Magenta, Yellow and Black information.
Infact Photoshop images are defined by color modes. Each mode is a combination of certain channels. The overall appearance of an image is the combined effect of these modes. As stated earlier, channels store the color information for an image. In Photoshop, there are four color modes, which consist of different color channels.
Following are the four color modes of Photoshop :-
RGB
The RGB color mode involves three primary colors- Red, Green and Blue. It consists of four channels-- a Red channel, a Green channel, a Blue channel and a composite channel which is a combination of the three primary colors. You can specify a value ranging from 1 to 256 for each channel.
Photoshop's RGB Color Mode uses the RGB model, assigning an intensity value to each pixel. For example, a bright red color might have a R value of 246, a G value of 20 and a B value of 50. When the values of all three components are equal, the result is a shade of neutral gray. When the values of all components are 255, the result is pure white; when the values are 0, the effect is pure black. In addition to being the default mode for new Photoshop images, the RGB model is used by computer monitors to display colors and is best used for editing images.
Although RGB is a standard color model, the exact range of colors represented can vary, depending on the application or display device.
Infact Photoshop images are defined by color modes. Each mode is a combination of certain channels. The overall appearance of an image is the combined effect of these modes. As stated earlier, channels store the color information for an image. In Photoshop, there are four color modes, which consist of different color channels.
Following are the four color modes of Photoshop :-
- RGB
- CMYK
- HSB
- Lab
RGB
The RGB color mode involves three primary colors- Red, Green and Blue. It consists of four channels-- a Red channel, a Green channel, a Blue channel and a composite channel which is a combination of the three primary colors. You can specify a value ranging from 1 to 256 for each channel.
Photoshop's RGB Color Mode uses the RGB model, assigning an intensity value to each pixel. For example, a bright red color might have a R value of 246, a G value of 20 and a B value of 50. When the values of all three components are equal, the result is a shade of neutral gray. When the values of all components are 255, the result is pure white; when the values are 0, the effect is pure black. In addition to being the default mode for new Photoshop images, the RGB model is used by computer monitors to display colors and is best used for editing images.
Although RGB is a standard color model, the exact range of colors represented can vary, depending on the application or display device.
CMYK
The CMYK color mode comprises of four color channels-- a Cyan channel, a Magenta channel, a Yellow channel, a Black channel and a composite channel that uses combinations of these four color channels.
In the CMYK Mode, each pixel is assigned a percentage value for each of the process inks. The lightest (highlight) colors are assigned small percentages of process ink colors, while the darker (shadow) colors are assigned higher percentages. For example, a bright red might contain 2% cyan, 93% magenta, 90% yellow and 0% black. In CMYK images, pure white is generated when all four components have values of 0%.
Although CMYK is a standard color model, the exact range of colors represented can vary, depending on the application or printing conditions.
HSB
This color mode is somewhat different from the other modes since it does not contain a value for the colors. Instead, it is defined by the three components of color which are Hue, Saturation and Brightness.
- Hue : The color reflected by an object is called its Hue. It is measured in degrees and is generally identified by the name of the color such as Red, Green or Cyan.
- Saturation : Saturation refers to the purity of a color. This channel contains information about the color purity, represented as the saturation of a color in an image.
- Brightness : In this channel, the colors are represented as degrees of lightness or darkness. For example, 0 degree brightness results in Black color while 100 degree results in White color.
Lab
Lab color is the intermediate color model Photoshop uses when converting from one color mode to another. The Lab Color mode has a lightness component (L) that can range from 0 to 100. In the Adobe Color Picker, the a component (green-red axis) and the b component (blue-yellow axis) can range from +127 to -128. In the Color Palette, the a component and the b component can range from +127 to -128. To print Lab images to other color Post Script devices, convert to CMYK first. The speciality of this mode is that its color gamut includes both the RGB and CMYK modes.
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