If you want to color one object in the black and white photograph, follow all the steps that are shown in this example.
Take picture: First we have to capture any black & white picture to modify.
Selection: To make selection of the object that you want to color by the Polygonal lasso tool (U key).
Color balance: Go to Image menu > Adjustment >Apply Color balance.
Adjust levels: Go to Image menu > Adjustment >Apply Levels.
Curves setting: Go to Image menu > Adjustment > Curves.
You will get it.
Recommend the tutorial