Mode

Some functions don't work in all color modes, so check your document to make sure it's in the best color modeoften RGBfor the operation you're attempting. You can simply check the title bar of the document to view its color mode. In general all options work in RGB mode but may not in another color mode, such as CMYK. There is another thing to check: the bit depth. Photo-shop CS2 has increased the number of functions that work in 16-bit mode, but there are still some that will only work in 8-bit mode. To change the color mode and/or bit depth, go to Image>Mode.