FOR THE MOST PART, THE UNSTOPPABLE MARCH of more powerful computers and software is a wonderful thing. However, some parts of the workflow have become more complicated. Not too many years ago, most of the photographs handled by computers were headed for a press, and that means they were probably saved in TIFF format in the CMYK color mode at 8 bits per channel. Once you saved a document to that format, you were done, and the document could be pulled out and reused later without much fuss.
With the rise of the Web and digital video, suddenly computers started filling up with RGB photographs at screen resolution in all kinds of formats, and there was often some degree of file-format confusion when print and on-screen media professionals exchanged files. The color mode and file format that worked best in one medium could create disastrous results in another medium.
Now, options abound all over the industry. You can store digital photographs at 8, 16, or even 32 bits of color per channel, in the CMYK, RGB, or even Lab color mode, and as a Raw, TIFF, JPEG, or layered Photoshop file format . . . and those are just a sampling of the actual range of possibilities. You might even wonder which RGB color space you want to use: sRGB, Adobe RGB, ProPhoto RGB or yet another?
Fortunately, there is a way to simplify this technological Tower of Babel. It all comes down to how much quality you want to maintain, how much disk space you want to use up, the amount of power in your computer, and most importantly, the kinds of output where your Photoshop documents must look their best.