CMYK is a color model in which all colors are described as a mixture of these four process colors. CMYK is the standard color model used in offset printing for full-color documents. Because such printing uses inks of these four basic colors, it is often called four-color printing.
Display devices generally RGB as color model. RGB and CMYK have different color Gamuts (Gamuts simply means the range of colors which can be produced) RGB has larger gamut than CMYK.
So now you know why your printed photos look different than what appears in the camera. One solution is to convert the RGB colors into CMYK colors so that what gets printed looks the same as what appears on the monitor. However changing the color scheme can distort the contrast and brightness of the original picture. For example pure Blue (R 0% G 0% B 100%) color is impossible to produce in CMYK. The closest attainable color is a shade of purple. Those unattainable colors are referred to as “Out of gamut”.
Fortunately software like Adobe Photoshop enable us to convert RGB files to CMYK. However many a times RGB suffers a loss of color when converted to CMYK Color Scheme. It may require a few touch ups to make the photos more colorfull and dense.