What we will learn



  • Histogram is a graph showing the number of pixels used in the image for a given color or intensity.
  • To view the Histogram go to Image > Histogram

  • The Histogram Screen will open up

Image Modes and Channels

  • Go to Image > Mode and you can select variety of mode from there
  • Let us view this picture in different modes
  • Open up the Channels Palette and click the channel you want to view


  • RGB Mode: Pixels are recoded as a combination of red, green, blue color values

Red Channel

Green Channel

Blue Channel

  • CMYK Mode:Pixels are recorded as a combination of Cyan, Magenta, Yellow and Black (K) color values

Cyan Channel

Magenta Channel

Yellow Channel

Black Channel

  • Lab Mode:Pixels are recorded by their Lightness value and color values on a green-red axis (the 'a' axis) and the blue-yellow (the 'b' axis) scale



Lightness Channel

A Channel

B Channel


Applying Color Fills

  • Select the portion you want to apply the color with the selection tools
  • Choose a foreground color

  • Go to Edit > Fill
  • The Fill Screen will open up
  • Choose Foreground Color in the Contents > Use
  • Choose an opacity percentage if you want a bit of transparency and press OK
  • Press Ctrl + D to Deselect the selected area
    Opacity 100%                                                Opacity 50%
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