This is a frequent question among beginners starting to learn Adobe Photoshop. Today I will show you one of the ways to change the background in Photoshop 7. We’ll be using a quick mask and the Refine Edge tool, so you’ll need Photoshop CS5 to work.
This photoshop tutorial will be pretty simple, and at the same time, the presented selection method in Photoshop is suitable for almost any image.
I also recommend reading the tutorial “ Select in Photoshop ”, it describes another way of changing the background in Photoshop.
At the end of this photoshop tutorial we will get this result:

HOW TO CHANGE THE BACKGROUND IN PHOTOSHOP
The complexity of selection in Photoshop depends on how close the background color is to the image itself. If we take, for example, a portrait of a man against a white background, then changing the background for him will not be difficult. We’ll look at a rather complex example. Let’s change the background in this dog photo.

1. Switch to the quick mask mode (Q key) (you can read more about masks in the “ Masks in Photoshop” tutorial ). Take a hard brush of the right size and start painting over the dog:


2. Moving on to the fun part. Press Q to apply a quick mask, it will turn into a selection. But the selection turned out, to put it mildly, miserable. Invert it (Shift + Ctrl + I). Take any selection tool and click the Refine Edge button.


The View parameter sets the background on which you will view the current selection. It does not affect anything and is needed solely for your convenience. I chose a black background, because it is most convenient to view this image on it.
The Edge Detection option is the most important, and it automatically separates the edges of the image from the background. Unfortunately, it is not perfect, but, nevertheless, it copes with the task quite well. To use this option, check the Smart Radius checkbox and select the optimal radius for your picture. Mine is 11.3px. If I twist the radius further, the tool will capture part of the background.
The options on the Adjust Edge tab adjust the edges of the selected image. Smooth sets antialiasing, Feather makes the edges soft, Contrast itself increases the contrast of the edges, and Shift Edge expands or narrows the selection. You can see the parameters for my image in the picture above.
Finally, the Decontaminate Colors option allows you to get rid of artifacts at the junction of the image and background. I use it almost always. There is one feature that you need to be aware of – if the color cleaning is active, after applying Refine Edge, a new layer with a mask will immediately be created, and the current selection is copied to it. I find it convenient.
So, apply Refine Edge and see:



