Photoshop has the following different kinds of layers
- Smart Objects.
One of the most versitile is the Adjustment Layer and there are 15 of them
Each adjustment layer is associated with a "Gadget-icon" and a Mask
Clicking on the "Gadget-icon" pops up a dialogue box that allows you to make adjustments to the layer(s) below...
In the example I have selected the Black & White Adjustment Layer using Photoshop CS 6
What I want to do is to "paint" some color back into the image of just the vending machine. That way your attention will be really drawn towards the color in an otherwise black and white image.
Here's how to do that.
Click once inside the White Mask to "activate" it... You'll see the double lines around the mask.
Press the "x" key on the keyboard, to cycle the foreground color with the background color at the bottom of the Tool Bar... We want the forground coplor to be BLACK
Press the"B" key to select a brush. You can make the brush bigger or smaller by pressing the Left or Right Square breket key.
Left square bracket makes the brush smaller, Right square bracket key makes the brush larger...
Paint over the Pepsi Machine on the Canvas, untill all the colors are Visible...
Painting Black on the Mask, blocks the black and white effect of the B & W adjustment panel, showing the colors from the layer below...
Here's the result