Using Adobe Photoshop CS4 is really an interesting experience! You can work on images for print or for the Web. You can improve photographs, re purpose them, or create original designs. Because printed images and Web images have different limits on the range of colors that they can represent, you need set the working color space for your project. Photoshop’s default color space is set to sRGB, a very limited color space intended to be viewable on even the lowest-quality monitor. sRGB is a good color space for preparing Web images; however, it is a much smaller color space than what better monitor can show and what printers can actually produce. Photographers usually prefer Adobe RGB (1998), a good color space for working with photographs and projects that you plan to print.
In Photoshop CS4, you can easily select your color space and save it as your own setting. Using Adobe RGB (1998) will make your printed colors look much better.
So for web , color settings in adobe Photoshop CS4 is sRGB
For flex printing and photo printing , designers should choose Adobe RGB (1998)
Go to edit and then color settings.
As shown in the image , Choose RGB according to the requirements and click OK
In the conversion options , select Intent as Perceptual for photography or Relative Colorimetric for a graphic design project. You can make a custom Color Settings preset in Adobe photoshop CS4. The name of the preset changes to Custom when you deselect any check box or make any other changes. Click Save after customizing your settings. Type a name in the Save dialog box and click Save. Your customized preset appears in the Settings drop-down list, ready for you to choose.