Teach Yourself Adobe Photoshop CS2.pdf - Online Public Access ...

This document was created by an unregistered ChmMagic, please go to http://www.bisenter.com to register it. Thanks .System (Windows)This option uses the Windows System palette.WebThis palette uses the 216 colors discussed previously. If you are planning to publish your work on the World Wide Web, thisis the "safe" palette. Otherwise, you might have problems with incompatible colors dropping out when an image is viewed with aweb browser.UniformThe Uniform option bases the colors in the palette on a strict sampling of colors across the color spectrum.PerceptualThis option creates a custom palette by giving priority to colors for which the human eye has greater sensitivity. Youcan use a local palette (based on the current image) or, if you switch to ImageReady, a master palette that draws colors from agroup of images you plan to display on a website or CD-ROM.SelectiveThe Selective option creates a color table similar to the Perceptual color table, but favoring broad areas of color and thepreservation of Web colors. Again, you can choose a local palette or a master palette.AdaptiveThis is your best bet for most work in Indexed Color. During conversion, this option samples the most frequently usedcolors from the original. Adaptive usually provides you with the closest match to the original image. This option also comes in bothlocal and master flavors.CustomIf none of the other options suits you, you can always build your own palette. See the Photoshop manual forinstructions.PreviousThis option simply remembers and reverts to whichever option you chose last time you converted to Indexed Color.CMYKAs you saw earlier, CMYK mode should be used only when your image is printed commercially. By converting to CMYK before you start toprint (and being aware of gamut warnings), you can make sure that your nice yellow banana or flower doesn't end up a muddy brown, oryour bright blue sky doesn't print as purple.Gamut refers to the range of colors that the combination of CMYK inks can print. Some colors are out of gamut, and can't be printedaccurately. Very bright colors, particularly oranges and greens, are often out of gamut, and would trigger the gamut warning. The gamutwarning shows up on the Color palette and looks like a small triangular traffic warning sign with an exclamation point in the middle.Converting Between ModesAll you have to do to convert between modes, at least mechanically (this is not taking image degradation or changes into account), ischoose Image Mode and then choose your poison.Although Photoshop uses the model (Lab) with the broadest gamut of color to change color modes (as if all the other modes are circlesthat will fit within Lab color), this is no guarantee that your colors will turn out the same in another mode as they did in the original mode.The rule of thumb is this, and I can't stress it enoughDo your work in RGB, even if you are going to output your images to print. Convert acopy of your image to CMYK immediately before you send it to the commercial print shop. To see whether all your colors are within theCMYK gamut, use the menu command View Gamut Warning. If you are going to publish your images on the Web, stick with RGB oruse Indexed Color, if file size is an issue. Knowing this will save you many hours of wondering why the Web page that looks great on theoffice Macintosh looks funky on the Windows machine you use at home, or why the yellow in your printed piece looks brownish.