Photoshop has a very usefull tool called layer masks. If you have ever wanted to emphasize the focal point of your image by making just that color and the rest black and white then this is the tool for you. Read on for a tutorial on using this usefull tool.
Initially layer masks can be tricky to grasp, but with a little experiementing you will soon get the hang of it.
I will start with a very simple example using just 2 colours. Create a new image and fill it with one color, I chose black. Create a 2nd layer and fill this with another color, I chose Yellow.
To add the layer mask select the Add Layer Mask button pointed to by the arrow above. The first thing to notice is that a new adjustment layer has been added in the current active layer.
Further to this you will notice that your color selections has turned to black and white, this is the only colors available in a mask, more on this later.
When you click on the mask area of the layer the icon to the left of the layer will change as below.
You can think of a mask as a very powerfull selection tool, by using any of the paint tools, pens or air brushes and painting either black or white onto it you manipulate the selection. Painting black onto the mask will let you see the layer below, and painting white onto it will show the layer above. Experiment on your own simple yellow and black image. Make sure you select the mask, and paint onto it in black and white.
After doing this simple example you should get the idea of how flexible a mask is in selectivly applying affects on layers. Their real power though becomes clear in a example using a photo. Load a photo of your choice, one that contains a area you want to draw attention too.
Create a new layer above the background layer, copy the image into the top layer and use your favorite method of turning the top layer into a black and white. I do it by adjusting the hue and saturation but you can use a sepia filter or something like that too.
Now enable your mask on the top layer and you are ready to start masking out the bit you want color. Here is my example with mask applied.
As you work on your mask you will start seeing how easy it is to undo mistakes by simply toggling the color from black to white. If you are still not 100% sure you got all the right spots you can view the mask in full size by holding the alt key while clicking on the mask.
In this mode it’s very easy to pick up on mistakes or areas you left out in your mask.
