If you’ve ever looked at the title bar of a document window in Photoshop, you might have noticed some numbers and or symbols after the titles name, something like “My Great Photo.jpg @33.3% (RGB/8*).” Decoding these symbols can let give you more information about your image. Here’s what it all means:
The percentage tells you the zoom level at which you are viewing your image, the closer to %100, the closer to the print size of your image. The RGB/8 portion of the title means that the image is in RGB color mode at a bit depth of 8, which is the most common. The asterisk after the 8 in the above example indicates that the color space of your image differs from the working color space of Photoshop. This can be important to know because the color output will differ from what appears on your monitor.
Many times you may make this choice on purpose when opening a document that has been created by someone else to do your final color corrections. If however, the symbol is a # sign, it means that Photoshop is not managing the color of your image at all. If you were to adjust the image and then print it, you will usually end up with some fairly unpredictable results.