Photoshop Tutorial - Remove An Unwanted Background By Isolating The Foreground

In this tutorial we are going to remove an unwanted background. To do so, we first have to isolate the foreground objects that we want to keep, in this case, some beautiful purple orchids.

When you open a file, photoshop places it in a window sized large enough to allow a full preview, while remaining small enough for other files to be opened and managed at the same time. This size is not suitable for advanced editing, so we are going to enlarge it. To do so, click the View menu, and click Fit on Screen. If you hover your cursor over an edge of the window, a double-arrow cursor will appear. Click and drag the edge to give yourself more editing room.

Now return to the View menu, and select Actual Pixels. This will give you a full, uninterpreted view of your file, with each pixel in your file mapping to a pixel on your screen.

Use the vertical and horizontal scroll bars to find a suitable area to begin your selection. I prefer to start at the edge of the image if the foreground is touching an edge.

The tool we will be using is called the Polygonal Lasso Tool. To select this tool click and hold on the third tool from the top on your toolbar, until the flyout menu appears. Choose the Polygonal Lasso Tool from the flyout menu.

The Polygonal Lasso Tool works like a dot to dot drawing game. Each click of your mouse defines a dot, and straight lines are drawn beween each dot. This may appear, at first glance, to be a poor choice for selecting curves, but it is not. The rule of thumb is, the tighter the curve, the more dots required to follow the curve with accuracy. I have found that this selection tool gives the greatest amount of control while making a selection.

While marking off your selection, keep in mind that edges are not always well defined. You will often have to make a best guess as to where the line should fall. You can make adjustments later, but they can be time consuming, so try to get it right on the first try. Also avoid double-clicking, an easy mistake to make when you have been laying down dots for some time. Double-clicking signals that you are done creating your selection, and joins the final dot to the first dot you made. This can be catastophic if done at the wrong time.

The best part of using this tool is that it does not matter where your mouse travels, as long as it is in the right place when you click to lay down that next dot. This makes it very forgiving to those of us with unsteady hands, or who get interrupted frequently while working.

To pan the screen for a better view of your subject, simply pull the lasso over the edge of the window, and the view will adjust accordingly. You can do this in any direction, as long as you are not at the edge of the file.

I'll now spare you the drudgery of watching me slowly create my initial selection, and fast forward to the point where it is almost complete.

This 18 seconds of quick time represents 30 minutes of actual work. The actual time it takes to complete an initial selection depends, of course, on the complexity of your file.

When you need your selection to follow the edge of your file, keep in mind that you can define dots outside the edge of the file, and the selection will trim itself to the exact edge. This is very handy for ensuring that you have not missed any pixels along the edge.

Here we have reached the starting point of our initial selection. If we hover over our initial dot, a small circle will appear on the lower right of the Polygonal Lasso Tool cursor. By clicking when this circle is present, we signal that we are done, and the selection closes. We could also have double-click from any point near or far from the initial dot, and the selection would close by drawing a straight line between the final and first dot.

We now click View, Fit On Screen, for an overview of our initial selection.

This is also a good time to save our initial selection so that we can reload it if necessary. To do so, click Select, Save Selection, and type in a unique name for the selection. In this case, I am giving it the name Outer, as none of the inner elements have been selected yet.

Here I am pointing out various inner elements, which in this case are peices of the background framed by the orchids, which need to be removed from the current selection.

I use View, Actual Pixels, to get the level of detail that I need to begin, adjust the size of the file window, and use the Navigator to move into position.

In effect, these inner elements need to be cut away, and to do so we hold down the Alt-Key while creating our first dot in their selection, signaling that the new selection is to be cut away from the first. If we were adding an element, rather than removing it, we would hold down the Shift-Key while creating our first dot. Release the Alt- or Shift-Key after creating the first dot, and proceed normally from that point forward.

I will now speed through the process of cutting out the inner elements to save time. Be very careful that you don't miss a small but significant cutaway.

Now that we are done cutting away the inner elements, we can click on View, Fit On Screen for an overview of our work, and then click Select, Save Selection to save our work. In this case I am going to call the saved selection Full, as the basic selection is now complete.

With a complete selection, we can finally remove the unwanted background from the file. To do so click on the Edit menu and select Copy. Click on the Edit menu once again, and select Paste. You will notice that a new layer appears in the Layers window in the bottom right corner of the screen. This is the new layer with the isolated orchids.

To visually remove the background, click the eye on the left hand side of the layer icon. This is a toggle. Clicking the same area again will visually replace the background.

You can now save your file, export a JPG, or continue playing with your new creation. Your full selection is saved as part of the file, so if you need to soften the edges or expand or contract the selection you can reload it and do so, but that is a subject for another tutorial.