So, there are two different color modes in photoshop: RGB and CMYK. RGB(red, green, blue) is the mode that is used for images that are supposed to be veiwed digitally. CMYK (cyan, magenta, yellow, black) is the mode that you should be using when printing something.
Determining the mode is the first thing you should do when editing an image, since if you decide that you want to print an image instead to just display it digitally half way through the editing process you might end up with a patchy and pasty image, which in most cases is not the result you're looking for. One thing you could do though, is merging the layers before changing modes, so you get something like this: