Follow below instructions
1. Open your image.
2. Duplicate the layer. Press shortcut "Ctrl +J".
3. Click on the first layer and choose "Enhance Menu>Convert to Black and White".
4. Add a mask to the first layer using "Layer Menu>Layer Mask>Reveal All"
5. Select brush tool , set foreground color as black and paint on the image to reveal the color areas of the second layer.
Do reply if you have any questions.