Here is a sample of photo colorization in which a sepia picture was colorized with very good results. This photo enhancement required a lot of fine detail work on the native dress which increased the fee. Fine detail, lots of people, and a complicated background also increase cost. To achieve the best results when colorizing a photo, it should be sharp, well exposed, and not have too many areas which are very light or dark.
Photo colorization is done by selecting one area at a time with the "Lasso" tool in Photoshop and then using "Hue Saturation" to applying a selected color. Another method is to paint the color on using the Photoshop "Paint Brush" tool.
Once an area like the man's jacket is selected, it can be converted to a whole range of different colors. It becomes tricky when you color faces because you need to do the eyes, hair, lips separately.
Not all photos should be colored. Many very old photos will look better in black and white or sepia toned images.