Re-Adding the Colour to the Petals
First of all make sure the 'Adjustment' layer is highlighted and that your Foreground colour is Black and your Background colour is White. Determine what area of your photograph you want coloured. In our example, we will add colour back to the petals.
Choose the Paint Brush tool at a suitable size. When you hold down your mouse button and start to move it over the image you will see that the colour reappears.
Carefully go over the petals to reintroduce the pink colour. If you make a mistake either right-click and draw over (effectively using the white Background colour) or swap the Foreground colour to white and go over the incorrect area.
You might want to zoom into the picture and use a smaller-size brush when painting the edges of the petals. Also make sure your Hardness and Opacity options are set to 100, though if you reduce the Hardness value you might be able to better paint the edges of the petal and not into the other areas.
Take your time as you paint over the petals. Paint all the areas you want in colour and when finished you will have a very unique Colour Popping picture, similar to the one on the left.
As you master this technique you will be able to create interesting and unique coloured photographs.